Looks like pretty much a done deal now. The Yankees won't give up anything of consequence besides money.
The verdict? Extraneous, IMO, but I can't kill it. Berkman becomes the primary DH against right-handers, at the very least. His performance against lefties this year has been brutal, as you can see here, and his career splits show how much better he always has hit righties.
More as it comes tonight...
UPDATE, 9:57 p.m.: As first reported by Joel Sherman, the Yankees will give up Mark Melancon and Jimmy Paredes to Houston, and pay about $3 million of the $7.5 million still owed Berkman. So the Astros can at least try to sell Melancon as a future closer. It never quite worked out with the Yankees and Melancon, even though he clearly had good stuff.
Furthermore, the Yankees have acquired Austin Kearns from Cleveland in return for a player to be named later. If you look at the righty-hitting Kearns' splits, you'll see that he's not an ideal platoon partner for Berkman or Brett Gardner (with Kearns playing leftfield against righties, and Gardner moving over to center), as Kearns has hit righties better than lefties this year. This acquisition speaks to how tired the Yankees got watching Granderson trying to hit lefties.