What are the available stylus pens for iPad?
If you want cheap, there's a youtube video on making your own stylus from the thin metallic-coated wrapper from a powerbar.  

I cleaned up and cut out a narrow strip of the stuff, looped it over the tip of a comfortable but dried-out rollerball pen, and it seemed to work as well as the expensive foam tip stylus for which I paid $15.

Added: Here's the Walt MossPuppet video.