Here is a program I have written for Toribash. It allows you to preview a head texture so that you can make one easier.
Just install into the Toribash folder, the installer will do the rest!
Instructions for use are in the ReadMe.
Please post here if you have any problems with the program or if you want any features adding.
I have only tested this on Windows XP.
Enjoy.
In case you are wondering how cool this really is... my new head (look at my avatar) was created with the help of THP and that picture was taken in THP.