The 2008 rates aren't published yet. I have been talking with Disney reservations nearly daily since June 13th. The most common answer has been mid-August. That would line up with the last two years.
You can call 407-W-DISNEY and book a room only reservation at 2007 rates. When the 2008 rates come out, your room only reservation will be adjusted or you can switch it over to a 2008 package.
Since there are 11 of you going, I would suggest you go ahead and book a room only reservation. At least that way, you are assured of getting the resort you want.
Another tip I would like to add, when calling Disney reservations, get them to give you a quote of what your vacation would have been in 2007. I was told that the rates go up approximately 6% annually. That'll give you an idea of what your 2008 rate will be. I'm adding about 12% so maybe I'll be pleasantly surprised!
Lisa