Well I didnt know this was started already
... It is not started yet but you can already start having fun and ill let you know when i organize it better.
The problem is that not any graphic will print well on shirts - I found that out when I had a lot of details on a design - it worked *okay* but didnt look good from a distance.. and that's not good
Make sure you remember that... Zoom out a LOT and see if still looks readable or clean enough to be on a shirt - thats a good test
As far as size and format, this isn;t the web so this is the specs:
. Units to use: INCHES
. Size: 10 INCHES x 10 INCHES (square)
. DPI: 300 (VERY important)
. FORMAT: TIFF (LZW compression OK)
*again* this contest isn't officially started yet, I am still fightingt his cold (now its my throat that hurts) and I haven't thought of allt he logistics (judging, etc).
Take care