A: Click on the link, and vote (click the "I want one" button). If the shirt is one of the top three that receives the most votes during this week's derby, it'll get printed. Then you'll be able to buy the shirt for $10-15.
Q: Help! I can't vote! How do I vote?
A: In order to vote in the Woot Derbies, you need to purchase at least one item from woot, wine.woot or shirt.woot. Once you buy something you get to vote in the derbies.
I just sent the design off for this to get printed at a new shirt site. If everything goes as previously discussed, it should be sold in their Kickstarter. I'll keep you posted.