Here's a link to Disney's site. Just click the "Map" link on the page, and a really nice interactive map will load. I think you'll need Flash on your pc for it to work, but it should install automatically if you don't already have it. Anyway, here's the link:
http://disneyworld.disney.go.com/wdw/parks/parkLanding?id=MKLandingPage
It's similar to the Disney map linked to in the first response, but this is interactive, in that you can zoom in/out, scroll around, etc.