The only 18 hole course currently is Kiawah Island. You also have the closest to the pin courses - theres 4 of them .
Bethpage Black (US Open)18 hole comes on line 25th May 09. Keep you're eye on the forum posts there's plenty info available you just have to look for it.
Not sure what else they're working on but theres plenty of variety for the moment. It will take you all of your time just to master one course.