first thing to be aware of is that DVC owners can book 11 months out at their home resort and many do...so availability 2-3 months out can definitely be spotty and some owners won't even bother responding to you for short notice requests since those requests are often a waste of time.
but if you are flexible and willing to consider larger resorts like SSR or OKW, there may still be availability. if you expect to book smaller resorts like BLT or BCV, you will probably be disappointed unless you start looking about a year in advance (although it is true that anything can happen - it's just more rare to find something 2-3 months out.)
also, it's getting a little dated but you should definitely scan through the [thread=1669863]
Considering Renting from a DVC Member?[/thread] thread...
just FYI, one thing that has changed from that thread is that renters can verify their reservation directly with disney now on this website:
http://mydisneyreservation.com/DVC
(updated to add: also, i don't think you can see the rent/trade board any more until you have 50 posts...that's a pretty recent change.)