Three days will be a whirlwind tour for WDW. To describe it as being HUGE is an understatement. Here is a link to some message boards where you can do some of your research: http://www.disboards.com/ You may also want to purchase a WDW guidebook. Amazon has excellent deals for used and new guidebooks.

IMHO, I think it will be challenging, if not impossible, to visit all four parks in a three day time period. If you do purchase a guidebook, read through and decide what attractions interest you the most. Most of them have strategy guides for visitors who only have a certain number of days in the parks. Beware, some of their plans include somewhat exhausting days as they try to help their readers complete the most activities in the least amount of time.

My husband and I love EPCOT, especially the world showcase area. It features several different themed country areas. When you enter a "country" you actually get the feeling as if you're visiting a village in a real country. In EPCOT they have a nightly laser/fireworks/water show called "illuminations" which is a MUST SEE. You can view the show from almost any location around the lagoon, just make sure you can see the globe in the water.

Have a fun trip. Keep asking questions, I'm sure there are lots of people on TOTV who know lots about WDW.