Snakeskins are strictly cosmetic; the skin is very thin, and would not add much protection to the back. This was my first attempt with osage, and my ham-handed working of the back down to the single ring left a bunch of minor tool marks. Since the ring was rather thin, I didn't want to sand it down further, so I just covered them up!
Here are the two primary internet resources I used:
Ferret's page:
http://groups.msn.com/ferretsarcherywebpage/_homepage.msnw?pgmarket=en-us/has a number of well-photographed articles, and a great section on making "board bows" from scratch.
George Tsoulaka's site:
http://www.angelfire.com/magic/jawge/Also lots of well-photographed build-a-longs.
Primitive Archer magazine has a very nice forum too.
The Bowyer's Bible series has everything you'd ever want to know, and they are about 12.00 bucks each in paperback from Amazon.
Most don't recommend osage for beginners, as the wood tends to be very "snakey" and also to have little branches and knots. I was lucky to get a nearly-perfect stave from one of the forum guys.
Far easier to work with a forgiving wood like hickory if you want to start from a small tree or sapling.
Excellent bows can be made from boards; hickory, red oak, ash, etc. All the above resources have good stuff on how to proceed.
Ferret (above) has a very nice tutorial on making a basic "board" bow with illustrations of what kind of grain to look for in a board. ( I went to a local hardwood dealer for a red oak board, and the second bow I made from that one is still shooting fine.)