Man, this can get tricky. I understand the concept of the vault from a marketing point of view, but from a consumer point, it sucks and is just plain annoying! Anyway, I'm going to try to give you a bit of an overview as best as I can here.
Currently in the vault/OOP/whatever you want to describe it as:
Snow White
The Lion King and its two sequels
Sleeping Beauty
Beauty and the Beast
101 Dalmations
Pinocchio
The Many Adventures of Winnie the Pooh
Peter Pan (although it is set to be rereleased in March)
The Aristocats (although it is set to be rereleased in March)
The Jungle Book (although it is set to be rereleased in October)
Bambi and Lady and the Tramp will indeed go out of print on January 31st.
The rest of the movies are all in print and most of them have achieved the highest level edition they will ever get. I would expect the Platinum Editions that are currently out to go back into the vault at some point in time (Cinderella, Aladdin, The Little Mermaid, etc.), although some of the less popular movies may never go out of print. The Platinum line also releases two movies every year (one around March and one around October) and is nearing the end of its line. Peter Pan is this year's spring release and The Jungle Book will be its fall release; although unconfirmed, next year should see Platinum releases of Pinocchio and 101 Dalmations, meaning that all 46 of Disney's Animated features to date will have seen a pretty significant DVD release. Also, all the Pixar films have and will remain in print. Supposedly, 2009 will mark the reissue of the Platinum line (meaning that starting with Snow White, the movies will be released out of the vault again). The problem with this becomes that by then, we could see a definitive verdict on the format war and all of the movies could be rereleased onto with HD-DVD or Blu-Ray discs.
I know this may all seem very complicated, so if you have more questions I would be happy to try and answer them. I'd also suggest checking out
www.ultimatedisney.com - they are the best resource on the web for all Disney media news and have complete listings of all animated and live action Disney films and where they stand as far as DVDs and being in or out of print.
I hope I helped you out a little!