[pak]

I may be confusing propagation speed and drift velocity--it's been a while since I learned this, and I think there is some way to rationalize that the net current is really moving close to the speed of light when you add/subtract the motions of all the individual particles, even if none of them in isolation are moving anywhere close to that speed.

In any case, this article explains the whole matter a lot better than I could.

http://en.wikipedia.org/wiki/Relativistic_electromagnetism