If you have a photo you shot with your iPhone that you want the whole world to see, you can use the new InstaShirt app to turn that image into a T-shirt for around US$20.
You have limited color choices and sizes range from small to XXL for men, women and children. As for the quality, there's not much to judge from at the moment. The examples shown on the InstaShirt site are fairly decent, but your mileage might vary depending on which version of the iPhone you use for a photo.
The InstaShirt app is a free download and shows you can create just about anything with your iPhone these days.
