making part of a texture invisible?

Um how would you make part of the texture invisible. For example, how would i set the texture file to alphatest or additive. Or is there another way you can make a specific color transparent?

Thnx
~ZWING

if your using adobe photoshop 6.0 or later, then you can just make a selection and delete it. However, there are certain parts of skins that cannot be deleted and team colors can never be deleted (they can be colored over, though).

edit: nm thnx, lol i shouldve looked in the stickied topics first