Okay, this discussion sucked so much that djbob sent me here to straighten things out. So here I am. Straightening.
Light has no mass. Massive objects gain relative mass as they approach the speed of light (relatively), with their relative mass approaching infinity as their speed approaches that of light. But that's all okay, since light is not massive. Evidence comes from its lack of inertia and gravitational field, since those are what define mass.
A photon is made of self-regenerating waves that are variations in the electromagnetic field. It's like the field that a magnet creates, except that it is very small. One of the waves that make up a photon is an electric wave, and the other is an magnetic wave. When the electric field reaches the vertex of its wave, it gets pulled back by the magnetic field, and vice-versa. Or something like that anyways. http://en.wikipedia.org/wiki/Image:Light-wave.png
Matter and energy are the same thing at fundamental levels. The difference isn't even well-defined in physics. Common usage of the word "matter" generally means things that have mass, or things that are tangible, or things that are made of atoms. Probably the distinction that would be most relevant to this discussion is that matter has mass.
As to Joe's idea about converting someone into light energy, sending them far away at the speed of light, then converting them back, I've got another idea. How about just finding out the exact composition of someone, sending that information far away through light signals, building an exact replica at the destination, and then killing the original? It pretty much achieves the same effect, but is easier to implement, and would cost less too!
Oh, and the idea of actually being able to achieve the speed of light given an infinite amount of energy in the universe doesn't really work. It would only get closer and closer to the speed of light, but never actually reach it. Infinity isn't really something that us humans can ever hope to achieve, y'know? Maybe there's an infinite amount of energy spread out over an infinite expanse of space, but an infinite amount of energy in a finite area (or is it volume?) isn't going to happen.
Ahhh crepes, that took a chunk out of my sleeping time.