This post is for a young lady I met this weekend named Natalie. I was telling her about making t-shirts using the Cricut machine, and I found the blog post I was thinking of that shows the technique.
Clever Someday is a great blog that has lots of fun tips for the Cricut. The video that shows how to make the t-shirts is here.
There are also lots of other fun videos for crafts to make with your Cricut. If you look in the right margin on Clever Someday, you will see a link to "Master List of Cricut Video Tutorials".