WE booked our July 08 trip last November.
You need to do it immediately..July is a VERY busy time in the world. I was in the CAA office in January and the agent at the next desk was calling to make a reservation at POP for July and it was fully booked. That may not be the case right now. If you can wait until August the rates will be in 'value season' which means cheaper and not as crowded.
I stayed at ASMo last year and it was great but the 3 AllStar resorts share busses which is a pain. The theme was a ton of fun. It is 100% eye candy to kids.