Because the dollar is so cheap now (at least from a European perspective) I have started to fight my reticence to buy goods over the Atlantic. As an example I have found Spreadshirt, the best "Design your own t-shirt" web site I have seen.
All in all I got my design shipped in a high quality t-shirt for around £10. Their flash based software lets you select between a big selection of t-shirt models, and you can upload your own design (raster or vector) and they'll print it on front, back and sleeves if you feel so.
I have only tried the raster service so far, but apparently if you send them a vector image the result is even better because they use a higher quality printing method - more details on their website.
I am going to design another one for my girlfriend, a white t-shirt with angel wings on the back, so I have doing some research.
Also, if you plan to order one, I have found these t-shirt template in photoshop format useful.