This one is really cool:
David Allen is a tattoo apprentice. He's also a reasonably handsome graphic designer.
...
Currently, his illustration experience has brought him into the world of tattooing. This site, allentattoo.com, is used to detail and chart the progress of his learning experience.
Not only do you get great insight into the art of tattooing, but you get fun Photoshop tips, too! It's a very young site, but it's off to a killer start.
(Props to Marisa @ Needled)