What are some of the techniques that go into the "forum signature" styles?

In my experience many forum signatures will have effects like these two:

http://img641.imageshack.us/img641/9862/coregomezsig4.png

http://img69.imageshack.us/img69/2312/crazymanip2v2.png

I'd love some tutorials or tips to get the effects that these images have.