2 great websites to check are
www.mousesavers.com
//allears.net - check out the menus and the pictures of all the WDW resorts
From Mousesavers -
The best times to go to Walt Disney World are:
Mid-November through mid-December (except the week of Thanksgiving). The weather is usually cool but pleasant, the Christmas decorations are up, special events are running, and the attendance is usually moderate. Expect crowds on Saturdays, especially at the Magic Kingdom. Disney's resorts typically fill up early for all of December, but this doesn't necessary translate into huge crowds during early December.
Second week of January through mid-February. It's cool (sometimes even a bit cold) at this time of year. This is one of the least busy times of year and hotel prices are lower. However, some rides will be closed for refurbishment at this time of year. The first week of January can be busy due to extended holiday vacations and the Walt Disney World Marathon. Avoid any holiday weekends.
First three weeks of May. The weather is warm in May, but usually not unbearably so. Crowds and hotel prices are moderate. Avoid Memorial Day weekend, which will be crowded.
Late August and entire month of September (even Labor Day weekend). It will be extremely hot, and this is peak hurricane season. Plan on taking afternoons off and visiting water parks. Crowds are low. Off-site hotels usually have their rock-bottom deals during this period, and Disney has offered "free dining" packages in this time frame each year since 2005.
During special events that interest you. Bear in mind that events held on major holidays usually attract significant crowds, however.
The worst times to visit Walt Disney World are:
December 26-31. This is the most crowded and most expensive time of year. Crowds get increasingly worse starting about December 20 and running through the New Year.
Mid-February through mid-April (or later, depending on the date of Easter), especially holiday weekends including President's Day and Easter. Expect huge crowds, high resort prices and expensive airfares, but usually very nice weather.
Midsummer (June through early August). Expect it to be very busy and extremely hot. To maximize your experience, plan on hitting the parks first thing in the morning. After lunch, take an afternoon break, then return to the park in the late afternoon/early evening. 11:00 am to 4:00 pm is the hottest part of the day and ironically the most crowded, too.
Other holidays. Among the other busy time periods are Thanksgiving week and any national holiday with a 3-day weekend (except Labor Day weekend).
During special events. Some don't create a lot of crowds, but some do.
Click here to see a detailed list of the most expensive and most crowded periods for 2008 and 2009.
Some less-known events that may affect crowds, park hours and/or traffic at Walt Disney World:
Cheerleeding/Twirl/Dance Competitions - Various dates each year, especially January-March. These usually don't have a lot of impact on the in-park crowds. The issue is that the Value resorts (All-Stars and Pop Century) play host to hordes of girls who can be extremely loud -- so you may want to avoid those resorts during competitions. Some events take place at Indiana Jones Stunt Spectacular in Disney's Hollywood Studios, so that attraction might be closed. Some of the competitions and events include College Cheerleading & Dance Team National Championships (January 15-18, 2010), National Dance Team Championship (February 5-7, 2010), National High School Cheerleading Championship (February 12-16, 2010), Twirlmania (February 19-22, 2010), Contest of Champions Nationals (February 27 and March 5-7, 2010), National All Star Cheerleading Championship (March 12-16, 2010), All Star Cheerleading and Dance Worlds (April 24-26, 2010).
Mardi Gras Week. February or March (varies annually - 2010 date: February 16). Many New Orleans schools have all or part of this week off, so families leave town the weekend before the holiday and head to Disney World in droves.
Grad Nites - Usually the last two weekends of April. (2010 dates: April 23, 24, 30 and May 1) Private parties for graduating high school seniors are held from 10:00 pm through 4:00 am at Disney's Hollywood Studios. On Grad Nites, the park will probably close to the public at about 6:00 pm. From 8:00 pm on, avoid driving in the area around the park as busloads of kids will be arriving, which may affect traffic.
Gay Days. First week of June (2010 in-park dates: June 3-6). Visit GayDays.com and OneMightyWeekend.com for more info about the two organized events. At most, only one park per day will be more crowded than normal; often there is no discernable effect on crowds.
"Jersey Week" - Usually the first or second week of November. The New Jersey schools have a teachers' convention (2009 dates: November 5-6), which is often close to Veterans Day. Lots of people take advantage of this time off to pull their kids out of school for the whole week and add on the weekend before and/or after, taking this opportunity to go to Disney World in the "off season." New Jersey is the single biggest market for Walt Disney World -- you do the math!
ABC's Very Merry Christmas Day Parade footage is taped in advance in Magic Kingdom, usually shortly after Thanksgiving (2008 dates: December 5-6). The exact dates aren't usually released until sometime in the fall. Unless you want to watch the production process, you may want to avoid Magic Kingdom, because it creates crowd problems. Also, some shows or parades may be cancelled or rescheduled. The Christmas Day Parade is broadcast on ABC on December 25 each year.
Pop Warner Week - The Pop Warner Superbowl and National Cheer & Dance Championships are held at Disney World in early December (2009 dates: December 5-12). The Value resorts and some of the Moderate resorts will be FULL of kids (both football players and cheerleaders). Expect a lot of noise if you stay there. This event can cause crowds at the parks in the evenings (not during the day, since they are busy competing) and there have been some unfortunate incidents, including violent fights between teams.
!
We didn't find the roads to be too bad and even with a night in a hotel a couple of meals and a couple tanks of gas we still came out ahead! 
