The Fender website makes it seem like you have to go to your local Fender dealer and "test-drive" a Fender amp to get a free t-shirt, but... not so!
Call musician's friend with the code they give you after watching a 3 minute video and they send you a t-shirt. Dunno if this has been posted but I haven't seen it anywhere.
http://www.musiciansfriend.com/soul-of-tone
I just did this and it took maybe 5 minutes. They even ship it to you free, and you can pick the size of the t-shirt. They put you on Fender's mailing list, but I was already on that anyhow.
Enjoy your free shirts, brothers and sisters!