I'm not sure that anybody ever confirmed that you can go to an Apple Store for scratch repair and Apple doesn't seem to have anything official about it on their website, that I could find.

However, word was that you could just walk in to an Apple Store and they would quietly repair it. If they do not, this product is recommended for scratch repair. It is called Apple Sauce Polish:

http://www.applesaucepolish.com/

Unfortunately it costs $19.95. Give your Apple Store a try first. The more complaints they get, the better, even if they don't repair it.

-Kevin S.