I like to keep a few Twitter feeds in my RSS reader, but can never remember how to get them from Twitter.
I found "Creating an RSS feed of a users Twitter timeline"...
However, I found there is a simpler method (for now)--replace USERNAME with the twitter name. This probably fails when a user changes names, but for stable usernames, this seems to work:
http://twitter.com/statuses/user_timeline/USERNAME.rss