WELCOME TO THE DIS!!
A good place for lots of information is the DVC area of this forum. Its towards the bottom of the page. If you lurk around there for a bit, you'll start getting a feel for it.
I can't help you with specifics to your questions, but I can tell you we have points at Animal Kingdom since June 07 and love having DVC. Availability at many of the DVC resorts is very limited right now. Rumor has it that when the next phase of Animal Kingdom opens next spring, it will be easier to get reservations. Its not impossible now, but very limited, in my opinion anyways. Take it for what its worth!
Good luck on making your decision. Another source of information is DVC itself. You can call and talk to a Guide who will explain everything and answer all your questions. I talked to my guide for a long time before making our decision. He was very patient, and did NOT PRESSURE US. NOTHING like the other timeshare companies out there. Disney doesn't have to pressure people, if they can't sell it to one person, there's another three people lined up ready to buy. So really, there is no pressure at all.
Good luck!