It costs @$19 by using the banner link at the top of this page(its a $3 discount). It's basically a guide book (like Passporter, etc) but you put in your travel dates and get more specific information like what parks are best etc for your specific time. I can't really get into any details because that is the agreement for signing up on his site. Also, he give your LOTS of info on each and every attraction so you can make great plans based on his info. Also, he does offer a money-back guarantee if you are not satisfied.
I am using it for the 1st time for my trip coming up in 9 days (OMG!!!!!) and I am totally loving it. There are also boards there with GREAT people who will help you plan everything down to what color underwear you should wear(ok, maybe not that detail but you get my point.)
Take a look around his link and read a little more about it. This has been only 1 or 2 times since I joined in Jan2006 that I ever heard of not being able to get to his site. Obviously any websitw will have glitches some time but don't worry by reading this thread that it is a common occurrance. In fact, I think you can see by the posts here that people can't even belive it's down (oh yeah, and don't know how to start their day without him!)
Good luck with your decision.