This actuality looks really cool! I used a Tribal Tattoo brush in PhotoShop that I have to make this. I built a header to go with it. So if your using the 2010 default theme for WordPress called Twenty Ten. You can easily add something cool to your site.
Custom Twenty Ten Background:
First upload the header.
Then upload the background image. Below are the display options settings.
Repeat: No Repeat
Note: I added Designerfied.com the the background image. Its behind the content area so you won’t see it.