Vanishing Tattoo is a great site for a wealth of information about tattoos: the lifestyle, the influence, and what to expect when you get one (to name a few topics). I strongly recommend you check out the entire site.
However, it is the Celebrity Tattoo section that always has me coming back. There is no resource on the web that has a more comprehesive source of Celebrity Ink. There are still a lot of gaps (some celebrities who are new to tattoos aren’t listed, as well as new ink for certain celebrities is not displayed). But, they do their best to remain current. For example, they do have Selena Gomez, who only got her first one in February, listed here.
You will be surprised at some of the famous people you find with ink. This site is definitely a good time-waster 🙂