Desiree,
Star Wars Weekends were just announced for 2010, and they are;
- May 21-23
- May 28-30
- June 4-6
- June 11-13
You are going to hit the second weekend right in the middle of your trip. That is great, as the very busiest crowds from the first weekend will be behind, you, but the buzz and fun will still be there.
So above I highlighted the link to the 2009 page for this event. They will probably update that with 2010 information as it becomes available. The park is literally transformed into a Star Wars world, complete with Stormtroopers patrolling the entry to the park, talking to guests and even posing for pictures. There are panel discussions with cast and crew from the many movies, meet-and-greet autograph sessions, and lots of Star Wars themed merchandise.
There is more than I can list here, so visit some of the great fan sites, like Matt Hochberg's StudioCentral.com. One event I am sure you will want to see is the Stormtrooper parade, complete with dozens of Star Wars enthusiasts decked out in their Stormtrooper uniforms!
Feel free to send me any follow-up questions!
Have a magical vacation, and may the force be with you!