1. Aurora Borealis
2. Blue openSuse
3. Cyber Eye
4. Purple Sunset Pines
7.Firefly/Serenity iGoogle Theme
8. Star Trek Theme
9. Drops of Life
There are some more, but they are not added yet in the iGoogle Theme directory. I will update this post as soon as they're there. Check the directory here.
Click the image and then "Add it now" in order to use the theme, that is if you have your own iGoogle homepage, if you don't have, make one!