How to make a basic signature

First go to http://planetrenders.net/ and find a render and download it. (you must register to see the full size of the renders there)
Then open photoshop and click File -> New

http://img514.imageshack.us/img514/2589/11454539.png

Width: 650
Height: 200
Background Contents: Transparent

Press OK.
Now click File>Place and place your render.

http://img46.imageshack.us/img46/1200/58977252.png

Here I put CS render.
Now put a text next to the render with your name.

http://img205.imageshack.us/img205/6533/69553544.png

For fonts go here: http://www.dafont.com/

Now click File -> Save as -> Format: PNG

Result:

http://img84.imageshack.us/img84/5917/nextlive.png