Why google patterns and download when you can make your own? This tutorial is really easy and anyone can do it.
Photoshop only ! (I'm not sure if this works with any other software, or which photoshop it works with, I'm using Photoshop CS 8.)
I'm sorry if you have a hard time reading the text... Maybe it was stupid of me to use the smallest one possible. XD
Also, thanks to Maru, who got me to think about making a tutorial (though I suppose she meant a signature tutorial, but meh).