There must be hundreds of guides to Disney World and believe me, I've read quite a few. My top tip is to plan, plan and plan again! If you know what parks you want to visit, which rides you want to go on and where you want to eat, you'll save time and arguments!
I whole-heatedly recommend buying The Unofficial Guide Walt Disney World as this answers just about every question worth asking about Disney World, Orlando and the surrounding areas. It also has pull-out park guides with step-by-step instructions on how to use your time in the parks most effectively. Two alternative fountains of knowledge are the Disboards site and forum, and the AllEars website which cover accommodation, attractions, restaurants and reviews.
Information on vegetarian and vegan dining in Disney is harder, but not impossible to find; While Disney is mainly aimed at the meat-eating guest, with a bit of research and planning, it's quite possible to do Disney as a vegetarian (but definitely more difficult as a vegan). I'll be putting together some links and tips which have helped us find some great veggie food in The Land of the Mouse over the next few days.
Read part 2 here.