OK, it is not official, but we can look at the contracts signed and such and pull together the 25-man roster very easily now.  Or at least do what the Astros must be doing.
Starters:
Roy Oswalt
Andy Pettitte
Brandon Backe
Wandy Rodriguez
Ezequiel Astacio (obviously there might be some competition in ST here)
Bullpen:
Brad Lidge
Dan Wheeler
Chad Qualls
Russ Springer
Mike Gallo
Trever Miller
That is 11 Pitchers.  My Concern with the bullpen is that only Springer is really a 3+ Inning type guy, which is somewhat nit-picky.
Now the Positon Players:
C: Brad Ausmus
1B: Jeff Bagwell (have to assume he will come back until you hear otherwise)
2B: Craig Biggio (quest for 3000 and icon status solidify this)
3B: Morgan Ensberg
SS: Adam Everett
LF: Lance Berkman
CF: Willy Taveras
RF: Preston Wilson
Bench:
C: Raul Chavez (Might be Quintero)
1B/3B: Mike Lamb
2B/LF: Chris Burke
UTIL: Eric Bruntlett
OF: Jason Lane
OF: Orlando Palmeiro
I would have to assume Luke Scott or a 12th pitcher make the team only if Bagwell cannot go, or a trade is made involving one or more of the 25 I just mentioned.