Photoshop help....

Hey all, I just joined the forums here and it looks like a great place, I thought maybe I could get some help here....
I am working on a picture for my forum signature at a couple of game sites and I am looking to create what you might describe as two metal panels that would appear to be like doors, opening to reveal a picture that will have a transparent binary layer over it. (don't ask, just smile and nod)
Now, I know how to do everything except the metal panels. I know it can be done, I've seen it at the forums. But the tutorials I have seen so far for metallic-looking panels are all consisting of a button-like object in the center of the screen.
Here's the one I am basing the "doors" off of:
URL
Now, in his tutorial the author uses channels as a "guide" of sorts as to where the metallic panels will actually show up.
Well, I think I can make the two doors on the top and bottom of the screen that way, but if I want the two panels to look "jagged"
I.E. they aren't just straight across, instead they are like,well teeth almost (i will draw a quick idea of it in paint and post it in a few)
Then I can't figure out how to do that. So what i am asking is,
How do I create "custom shapes" in channels in photoshop?
I thought maybe I could pull a microsoft paint and jsut draw lines and "connect the dots", but it doesn't seem to be working. Too bad they couldn't have modified the "Polygon Lasso" tool and made it a "Polygon Drawing" tool.
Any help would be EXTREMELY Appreciated, and please, feel free to ask questions if I confused you (I wouldn't be surprised, it's a very complicated idea and it took forever just to come up with.)
Thanks,
Digerat
EDIT: here's the image of what I meant, (it was a paint image and it took the lesser part of 10 seconds so STOP LAUGHING!!! lol j/k)
URL

ok make a smal texture of the metal after u have it click on the top menu

EDIT--------DEFINE PATERN

then do ur doors and use that patern to fill it

Ok, thanks a ton,
Also, when you say, "Do your doors", Can I just draw the shape with lines? Or how would I get that shape?
Thanks again,
Digerat

you could draw it as a channel, as a vector mask or as a work path