Been using TouringPlans.com (requires $10 subscription for full access, little less if you buy their guide book which is also excellent) and easyWDW.com (free, but in a blog form so navigation can be interesting).
MouseSavers.com is also a great discount resource. Sign up for their monthly newsletter for even better deals.
I'm also liking this Transportation Wizard for calculating time between parks and resorts. Helps to see if my park hops or ADRs are realistic in terms of commuting.
Been planning my first trip with these tools. The DIS boards have been equally invaluable.
I used Tour Guide Mike for our last trip & it was invaluable. The actual website hasn't been updated in ages, though. He really teaches more about how to tour than just handing you a plan. I paid for it again, just to have access to the private forums!! I'm also incorporating some of those mentioned above, as far as crowd calendars go, anyway!
Mousesavers is definately an awesome site for Disney knowledge and the ins and outs of costs and how to save money as well as amazing Disney information across the board. Allears is another personal favorite that has great pictures of all of the resorts and lots of great overall Disney material. Definately check out the EasyWDW site as well. The site is chocked full of great information and tips and is totally up to date with all the goings on. They also have a "board" like this with some very knowledge people.
agreeing with Touringplans.com the info they supply is very valuable in my eyes. And I had no problem paying the couple extra bucks to join the website. Their book is deff. the way to go to. I get it every year, and I love all the quirky little stuff they throw in.