I'm worried this may mean TMs cannot be transferred over from 4th Gen. games, and that they will therefore reset the TM list. If TMs can be used multiple times, it stands to reason they won't have an x01 next to the TM name in the Bag, similar to how HMs and Key Items currently work. And as Pokemon can't hold HMs, could the same hold true for the new TMs? Which would imply you can't trade TMs over from old games."TMs will no longer expire after one use - you can use them as many times as you want, like HMs!"
BEST. NEWS. EVER!
I don't know from a programming point of view whether they could make it possible for Pokemon to hold Key Items / HMs / New TMs, in which case when you transfer a TM from a 4th Gen. game to B&W it would go from x01 to having no number next to it. I hope this is what happens, otherwise there are going to be tons of illegal move combinations to keep track of.
EDIT: Now that I think about it some more I don't see the second alternative happening. Imagine the scenario where you transfer over two Pokemon holding Focus Punch. Now you have two TM01's in B&W, but they don't have an x01 next to them... this is really messy. So I'm like 90% sure they will reset the TM list. I suppose they could also not let you transfer TMs, but make all the old TMs available in B&W.