Seems like this all happened pretty quick. Ken Rosenthal gives us an update on the state of the Berkman situation:
A twist on Berkman: Due to his 10-5 rts, trade to #Yankees would not be official until after expiration of 24-hr window...Source says he gave approval earlier today, so everything should be OK. But official word would not be until Sat. aft. He can rescind at any point during 24-hour window, but source doubts that will happen. Announcement likely tmrrow aft.
Lance Berkman has pretty much every reason to accept this trade - he hasn't been to the playoffs since 2005, and he'd be joining baseball's best team for about three months before going back on the market, at which point he could re-sign with the Astros if his heart desires. So the Yankees, for all intents and purposes, have found their new designated hitter.
What remains to be seen is what the Yankees will give up in return. Sans Berkman and Roy Oswalt, the Astros will be a very different team to watch.