[Nate]

1. Go here: http://twitter.com/
2. Hit the Sign up button
3. Fill stuff in
4. Confirm via mail your inscription
5. Follow some dudes, I personally recommend:
   http://twitter.com/OddBlog
   http://twitter.com/AlfMudokon
   http://twitter.com/AbeMudokon
   http://twitter.com/jawltd
   http://twitter.com/stewartgilray
   
   Optional
6. Install the Echofon addon for instantaneous updates of the tweets posted by the guys you follow in your favorite browser.

Or he could just occassionally browse to those URLs and not bother joining.