I can't recommend this highly enough: Subscribe to Tour Guide Mike (
www.tourguidemike.com ). I've used him the last two years and I swear, if you follow his advice you won't have to wait in line for more than 10-15 minutes at ANY ride, even during high season.
We got burned 3 years ago after having an absolutely miserable vacation with the crowds, heat, etc. Then we tried TGM and were absolutely amazed at the difference. Instead of having a "Disney Death March" through the parks, coming close to heat stroke a couple times, we had an enjoyable, FUN experience...the way Disney was meant to be.
To me, that's EASILY worth the twenty bucks. Highly recommended.