What do you need to know to begin developing themes?

[Tye]

Is there anything that I need to know before beginning to develop themes? Also if anyone happens to know of any places where I can get a tutorial telling you how to develop themes or what part of the form changes the theme

[Aaron]

You may find this link interesting. It's a sticky in this board.

http://www.simplemachines.org/community/index.php?topic=16843.0