Here's some text from our friends at graniph, who if you don't know, you'll have to check out. They have good design, nice shops, and are growing.
The Japanese Design Tshirt store graniph is arranging the international T-shirts design award vol.2 from the 1st of February until the 31st of March 2008. We are calling young artists, designers, illustrators and photographers to send us their ideas for T-shirt designs. Everyone is welcome to apply regardingless age, gender or artistic background. The winners will receive cash prizes, will be promoted through the graniph website and the international press and have their design printed on a graniph T!
Detailed information and the application form are available at: www.graniph.com/award
One thing their text didn't say are the prizes: so, give it a shot if you like the terms.
1st place $9000 and they might make your shirt
2-10 $900 and they might make your shirt
40 bronzes $450