Eggs no longer work, due to Game Freak messing up the breeding code. This may be fixed in the international release, however.
Everything else is pretty much the same, with a few little differences. For example, Entralink Pokemon no longer require C-Gear seeds to determine IVs, and the IVs are instead obtained the same way as any other Pokemon.
It's basically the same as on a DS lite or phat. There are only a few minor differences, like timer0 ranges being different, and needing to keep track of seconds on an external clock or timer. C-Gear seeds are completely gone in BW2, anyway.