I designed and bought this shirt through Shirtmagic (see my 'I Made A Shirt' post last week).
I went with the 'digital printing' option instead of 'silk screened' which turned out okay I think. The color is much thinner than expected, but Silk screened shirts look cheese-dick, so regardless the outcome of the digital print I would have been happy.
I have made shirts through zazzle too; that site, even though has great options for design, is very fucking slow. It's the photobucket of t-shirt sites. I highly recommend Shirtmagic, it was a very smooth deal.