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Do you believe it's possible? Or more importantly, do you think we'll ever have the capabilities to travel through time significantly?

Yes, I'm very excited for the LHC. I thought that when you traveled through a wormhole you weren't technically moving faster then light, you were just changing the distance in between two places. From what I understand wormholes are the key to time travel because if you can warp space you can warp time therefor a wormhole will do both. I also thought there was no limit to how much energy one can put into an area of space.

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Also I heard that if you get up to light speed, you will somehow age slower as time around you ages faster and that would be a way of time travel. Its an interesting theory.

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Well, at the point I'm at in learning Physics, we tend mostly to think of things in terms of reference frames and Relativity instead of treating space as some kind of warpable fluid.
In which case, the light clock thought experiment one usually makes to picture a Relativistic event (ie, when something is going close to speed of light) doesn't work.
Explanation;
You have 2 mirrors, one of which stays in your lab, and the other one comes rushing past at some large fraction of the speed of light.
The time taken for light to travel a given distance is the same for every reference frame in the Universe.
The mirror travelling past has a person on it, and he descides to flash a torch at the mirror in the lab as he goes past so that it will reflect back.
The flash, if both mirrors were still, would have to travel the current distance between the mirrors, hit the lab's mirror, and come back.
But the second one is moving, so if the person on the second mirror flashes a light directly away from the mirror.
Since the flashlight is travelling very fast, the light emitted from it is not only moving away from the mirror, but moving with the mirror as well, so that the person with the flash light sees the light moving off in a straight line.

From the view of the mirror in the lab, however, the light is moving diagonally, and so has to cover a greater distance to get where it's going.
The Speed of Light in a vacuum is constant, so the person in the lab views it's total speed still to be the speed of light, even though it's travelling outwards (towards mirror 1) at less than the speed of light (because it's going diagonally).

Sorta like this;
http://upload.wikimedia.org/wikipedia/en/a/a5/Time-dilation-002.svg
Where A and C are mirror 2 before and after it passes B (mirror 1, in the Lab) respectively.

The solution is not that the light goes at different speeds for different people, but that time slows down from the point of view of someone at either mirror looking at the other mirror.
i.e. the mirror in the lab sees the light travelling outwards from the second mirror more slowly, since it's mostly moving forwards in time with the second mirror and only a small component of it's velocity is devoted to moving towards mirror 1. But to mirror 2, this light is moving outwards at exactly the speed of light, So mirror 2 experiencing time at a much slower pace than mirror 1 from mirror 1's perspective.

Time Dialation.

Hence, if you go ever closer to the speed of light and use the flashlight from the second mirror, you have to make the flash further and further back before you come past the mirror in the lab, so that the light hits the mirror and bounces back again, because increasingly the component of the light's speed in the direction mirror 2 is travelling gets closer and closer to the full light speed.

So what happens when you shine a light from a craft travelling faster than the speed of light?
Say you're going at 1.5 times the speed of light.
You'd be speeding along with mirror 2, but if you flash the light directly outwards from your mirror, towards where the lab mirror will be when you go past, it will end up having to go at 1.5 times the speed of light in the direction you're travelling in in order for you to see it move away in a straight line, which of course is impossible.
So say you flash it very nearly backwards, so that it's going in about the opposite direction to the direction you're going in. Then according to the Lab's mirror, it's only going at half the speed of light, which is ok.
But it will never be able to bounce back and get to mirror 2 again, so the clock is broken; you can't measure time between either reference frame anymore.
Time still has to progress though, doesn't it?
So in order for someone to be going faster than the speed of light, one can't avoid going in directions other than forwards in time from the point of view of a frame of reference which sees you going faster than the speed of light.

Sorry, that's really long, but I assumed from your last post that you're familiar with time dialation, at least a little, so... sweatdrop
If not, don't worry, you should be doing it soon in Physics anyway and the above argument should make more sense.

As for limits on how much energy can fit into one space, the Planck Scale says that (because of the Uncertainty Principle) at scales corresponding to the Planck Length you can't measure useful distances anymore - our concept of space breaks down. The Planck Energy is the energy that corresponds to this.
ie; a photon has energy E=hf, Planck's Constant*it's frequency.
c = f*L, the speed of light = the frequency*the wavelength.

Substituting, E = h*c/L

When it's wavelength L is the Planck Length, then E is the Planck Energy. So it should be the maximum energy that a photon can have, because (we think) you can't get lengths shorter than the Planck Length.
Hence, together with some freaky Quantum Black Holes eating up information whenever you try to probe anything of such length with a photon that energetic, we think it's the most energy you can meaningfully have in one place in the Universe. But we don't know for certain really, because predicting things on this scale requires a working Theory of Quantum Gravity.

Thanks for that Rugged. Very interesting. And yea, they've sent particles close to the speed of light and seen that they've decayed at different rates proving time dilation.

Totally!

Do I think it's possible? No.
Why? No reason really, just think it's a bit "far fetched".

What would kill us? I suppose if you do it faster than light travel you'd die from the heat/gravity of your own kinetic energy. But there are other ways.

I have argued in other forums, and will do the same here, that time dilation caused by relativity is not the same as time travel. A fly has neural connections that are shorter and faster than a human's, so flies can react more quickly than a human (why it is hard to swat a fly). From the fly's perspective, time seems slower (a fly is supposed to be able to see the individual frames of a movie where to a human they form a continuous moving image). This, however does not make the fly a time traveler. Some living things can go into suspended animation. Their metabolism slows and so time will seem to travel much faster around them, but again this is not time travel. Relativity says that if you travel in a spaceship near the speed of light, then time outside the ship will seem to you to speed up. This supposedly allows you to travel to the future by having your own relative time reference shifted. But this is not really time travel. Why? Just because the speed of time may be relative, does not change the fact that a light speed traveler and an observer (or generations of observers if necessary) always exist at the same time. They can always observe eachother, because the speed of light is fixed. There is no disappearing or reappearing, such as the DeLorian does in the "Back to the Future" movies. Since the two always coexist, despite the differences in how they observe time, no time "travel" can be said to have occurred. That is how I would interpet things.