Stoned Society...shirtchamp has wholesale shirts at low price
Yes, make sure you always get permission from the copyright holder, otherwise you could land yourself in a serious pickle!
So you want the t-shirt printing company to actually market and sell the product for you and just give you the profit??
I can make a suggestion to a T-Shirt printing company that are pretty cheap - http://www.krowmarkworkwear.com/
They specialise in wholesale workwear, but they do hoodies, t-shirts, polo necks and just about anything made from cloth.
Also, have you thought about embroidery rather than printing? It tends to last longer...Plus you dont ruin it with the iron!
Hope that helps buddy.