I stumbled upon a very good book about robotics called Robot Modeling and Kinematics , by Rachid Manseur. It is completly about modeling robot arms, and nothing about navigation, etc.

One of the neatest things is that it comes with a bunch of programs that create VRML files to simulate robot arms according to parameters you specify. You run the program, type in some specifications for an arm design, and you can view the resulting animated simulation in your web browser. It uses tons of matrix math, which I don't know much about, but it actually is a fun way to learn about matrix math...;-)

For the FIRST Robotics competition this year, my team used a very simple, one joint robot arm. It worked well, and I don't think I would change it, except perhaps to add a single-axis wrist. I was able to model our arm very easily using the programs that came with the book, and this will help with future designs of robot arms...

I'm actually glad that I didn't find this book until after the FIRST build season; no telling what I would have suggested for out robot after seeing the cool ideas in the book.

One more thing, there are a number of mistakes in the book, but you can download an errata file from the publisher's web site here.

I will post more as I get into modeling robot arms...