How can I do Alpha Channeling in Photoshop 7?

Well, my first time to make/edit some skins using Photoshop 7 and I would like to know how to do Alpha Channeling in there.

If it can't then I'll just post my skins here and ask a person to alpha some things out.

Thanks in advance.

there is a targa plugin you can get at adobe's site under patches I think. I tried it and I never had success. Photosop 8 (CS) is great for editing skins and alpha channels so get your hands on it if you can.