We have looked at Island shapes and compared them to the lost Island, checked co-ordinates to establish where it may be, and have come up with a few different idea's.
So I looked at volcano's, plate tectonics, seafloor spreading, geomagnetic reversal and came up thinking if the Island was in a different timeline, it's shape may have changed.

Plate Tectonics (http://en.wikipedia.org/wiki/Plate_tectonics)
The lateral movement of the earths tectonic plates Earthquakes, volcanic activity, mountain building, and oceanic trench formation occur along plate boundaries.

Seafloor Spreading (http://en.wikipedia.org/wiki/Seafloor_spreading)
This occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. Seafloor spreading helps explain continental drift in the theory of plate tectonics.

Geomagnetic Reversal (http://en.wikipedia.org/wiki/Geomagnetic_reversal)
A change in the orientation of earths magnetic field such that the positions of magnetic north and magnetic south become interchanged. These events, which are believed to last a few hundred to a few thousand years, often involve an extended decline in field strength followed by a rapid recovery after the new orientation has been established.

Now consider the possibility Dharma was effectivly controling the earths magnetic field with the Swan Station. Magnetic fields effect shifts in the tectonic plates.
Have you heard that as the earth continues on it's alligned magnetic path around the sun it keeps drawing nearer effectivly ending life on the planet.

Now moving on.

The majority of the world's active volcano's occur along plate boundaries, with the Pacific Plate's Ring of Fire (http://en.wikipedia.org/wiki/Pacific_Ring_of_Fire) being most active and famous.
One of the Islands situated in the ring of fire was Ross Island (http://en.wikipedia.org/wiki/Ross_Island) with a volcano called Mount Erebus (http://en.wikipedia.org/wiki/Mount_Erebus) which is the southernmost active volcano on earth.
Here are the pictures of the lost Island and Ross Island.
http://gallery.lost-media.com/displayimage-search-0-12.html
http://en.wikipedia.org/wiki/Image:RossIslandMap.jpg
If you consider plate shifting this could fit the bill, I know the co-ordinates are probably off and that could add a lot of argument, hell the Island could be undiscovered up to this point and there is one that looks just like the losties.

If anyone finds some similar Islands that fit the bill please post a link.

This is a brilliant start to something awesome!

Would that imply that the island might be in the far future or far past? ... I mean assuming they used EM energy to manipulate the plates, it would certainly take a long time to create new formations, no?

This is a brilliant start to something awesome!

Would that imply that the island might be in the far future or far past? ... I mean assuming they used EM energy to manipulate the plates, it would certainly take a long time to create new formations, no?
Good to have you on board Mikey.
There are essentially two types of forces that are thought to influence plate motion that are Friction (http://en.wikipedia.org/wiki/Friction) and Gravity (http://en.wikipedia.org/wiki/Gravity).
I can't say for sure how quickly plate shifts occur, but the Swan seemed to have the potential to accelerate the process.
Wiki Quotes

Gravity and Quantum Mechanics

Several decades after the discovery of general relativity it was realized that it cannot be the complete theory of gravity because it is incompatible with quantum mechanics. Later it was understood that it is possible to describe gravity in the framework of quantum field theory like the other fundamental forces. In this framework the attractive force of gravity arises due to exchange of virtual gravitons, in the same way as the electromagnetic force arises from exchange of virtual photons This reproduces general relativity in the classical limit. However, this approach fails at short distances of the order of the Planck length where a more complete theory of quantum gravity is required. Many believe the complete theory to be string theory.
It is notable that in general relativity, gravitational radiation, which under the rules of quantum mechanics must be composed of gravitons, is created only in situations where the curvature of spacetime is oscillating, such as is the case with co-orbiting objects. The amount of gravitational radiation emitted by the solar system is far too small to measure. However, gravitational radiation has been indirectly observed as an energy loss over time in binary pulsar systems such as PSR 1913+16. It is believed that neutron star mergers and black hole formation may create detectable amounts of gravitational radiation. Gravitational radiation observatories such as LIGO have been created to study the problem. No confirmed detections have been made of this hypothetical radiation, but as the science behind LIGO is refined and as the instruments themselves are endowed with greater sensitivity over the next decade, this may change.



Graviton

In physics, the graviton is a hypothetical elementary particle that mediates the force of gravity in the framework of quantum field theory. If it exists, the graviton must be massless (because the gravitational force has unlimited range) and must have a spin of 2 (because gravity is a second-rank tensor field).
Gravitons are postulated because of the great success of the quantum field theory (in particular, the Standard Model) at modeling the behavior of all other forces of nature with similar particles: electromagnetism with the photon, the strong interaction with the gluons, and the weak interaction with the W and Z bosons. In this framework, the gravitational interaction is mediated by gravitons, instead of being described in terms of curved spacetime like in general relativity. In the classical limit, both approaches give identical results, including newtons law of gravitation.


Friction

Friction is the force that opposes the relative motion or tendency toward such motion of two surfaces in contact. It is not a fundamental force, as it is made up of electromagnetic forces between atoms. When contacting surfaces move relative to each other, the friction between the two objects converts kinetic energy into thermal energy, or heat. Friction between solid objects and fluids (gases or liquids) is called drag. Friction in an electronic circuit is called resistance.

But wait theres still more and this concerns GOOD VIBRATIONS.


Beginning in the 1950s, scientists including Harry Hess, using magnetic instruments (magnetometers) adapted from airborne devices developed during World War II to detect submarines, began recognizing odd magnetic variations across the ocean floor. This finding, though unexpected, was not entirely surprising because it was known that basalt -- the iron-rich, volcanic rock making up the ocean floor-- contains a strongly magnetic mineral (magnetite) and can locally distort compass readings. This distortion was recognized by Icelandic mariners as early as the late 18th century. More important, because the presence of magnetite gives the basalt measurable magnetic properties, these newly discovered magnetic variations provided another means to study the deep ocean floor. When newly formed rock cools, such magnetic materials recorded the Earth's magnetic field at the time.


I hope this is enough to convince you the swan was manipulating the earths magnetic field.

Gravitons still aren't totally accepted yet, though it is a TV show.

I really expanded my theories on the swan and had to post a new thread in the spoiler section.
http://thefuselage.com/Threaded/showthread.php?t=82029

I think you're on the right track with the plate boundaries being probable places of volcanic activity, and therefore, the island. But there are also "hot spots," like Hawaii, where magma rose up to the surface in the middle of plates. That's why Hawaii kind of looks like a dribble. The magma kept coming straight up while the plate was shifting.

I agree with you that the Swan was connected to the earth's magnetic field, but I seriously doubt even the most powerful magnetic force scientists could build, even if it was as big as the entire island, could hope to control or even slightly influence the direction of the magnetic field. We're talking HUGE forces of nature here.

Last, I admire your effort to find a location of the island. I'm very curious myself. But I think that the point we shouldn't forget is that it is probably not on a map. Nobody knows about it and Naomi even said they were looking in the middle of the ocean, meaning no known mapped islands around. (Unless it was discovered after the island lost its invisibility! That would work great with the storyline.)

And for appearance of the Lost island, it does bear a striking resemblance to Oahu, where it is filmed, if you compare geographic maps of Oahu to Rousseau's map. The mountain ridge on the west side with the smaller mountain area on the right. Except there is a crater where Pearl Harbor would be.

I think the biggest clue we have as to the island's whereabouts is from Jack's maps in the future. We can kind of get an idea from the lines he drew (of flight paths of planes he's been on trying to get back?) on his maps of the Pacific. They all intersect at different points if you extend them out, so he must not know exactly where. But he's got a better guess than us. It also looks like he's trying to backtrack Michael's route away from the island with the several lines on the map on the right side, with the same angle line (325 degrees?) jutting out of each, and the protractor.

Well, we got plently of time to work with the clues we got (and plently of clues as well; Too bad we have more mysteries) until Lost comes back with Season 4. Happy hunting!
100%
Just thought of one more thing...

I'm currently rewatching the series to get my fix until season 4. In the scene where Sawyer, Kate, and Karl escape from the other island, Karl is talking about watching/naming the stars with Alex, and how certain constallations are visible in different parts of the sky in that time of the year. With that kind of knowledge, I bet either Alex or Karl could narrow down the location of the island quite a bit, if they had a star chart for the Southern Hemisphere sky that shows the different constellations thoughout the year and the times they are in what part of the sky.

Go science!