Light Speed

This site provides a great overview of the possiblities for faster than light Travel and Faster than light Communication

math.ucr.edu...

I'm glad to see someone else recommends Baez' site. I would like to add this one.

Also, about tachyons, there is no experimental evidence of their existance. Charged tachyons would produce massive amount of cherenkov radiation, because if they lose energy, they actually go faster. Thus losing even more energy from cherenkov radiation and speeding up even more, etc. This is explained somewhere on Baez' site as well. They would also violate causality, but that always seems to be the least of the concerns of FTL proponents.