At starcraft2.com, you can already download two nice Starcraft 2 posters and help to unlock more content by taking the Starcraft 2 test, submitting fan art and showing your support on Facebook.
So far 57% of content have been unlocked.
Also, if you’re a creative person submit your fan art here:
Here’s one of the Starcraft 2 postsers that has been unlocked:
So, head over to http://us.starcraft2.com/dominion/ and help to unlock more posters and goodies.