Here's another FREE goodie brought to you by Pixel Moshpit for your TShirt designs. You'll find a layer to "Paste Artwork Here" and all you have to do is just that, Paste it. Then all you have to do is export it out! You can also change you background to whatever you'd like before exporting to give it a more professional look.
Thanks again for all of the support. Remember as well, to share this if you find it useful!