You have until 12 noon PST on 6/6/11 to submit to the Challenge. Just upload your fan movie with "Star Wars" in the title, and add it to the Star Wars category to be considered for a number of awards. One entry will be picked to air on Spike TV and one lucky submission will be crowned the "George Lucas Selects" recipient by Mr. Lucas himself!
For all the official details check out the Star Wars info page, and for more up-to-the-minute details, keep up with the blog. Check out past winners here.