for the first week in november 2010 - it's not great odds but it's possible. (food and wine at epcot make the epcot resorts a lock to be booked up, though - so BWV and BCV are almost certainly out.) the first week of december is much more popular among DVC owners.
DVC owners can book their home resort at 11 months out, and many do to make sure they have a spot. at 7 months, any owner can book at any DVC resort that still has availability.
if you are looking for something rare (like AKV concierge villas) or otherwise tough to get (like early december at the wilderness lodge villas), then you need to book right around the 11 month window. usually there is still some availability at the 6-7 month window.
at 3-4 months out, you are really "last minute" in timeshare terms but if you are flexible (and OK with the larger resorts like SSR or OKW), it is still possible that some studios are available. it's worth a call...