I recently sent a couple of my photos off to be printed on canvas. For more than a year I promised my cousin a print as a housewarming gift. This time around I chose http://www.canvaspop.com/
The prints come out really nice and they do a great job stretching and framing the canvas (the image is warped in the camera, not in real life). I'm not generally a fan of photos printed on canvas, but I was happy with this one.
I had one other project printed on canvas. A photo manipulation that looks a lot like a painting. This one really looks great on canvas. I didn't get it stretched or framed. Someday I will have that done. If you are looking for quality canvas prints at reasonable prices, check out CanvasPop.