NOTE: As of October 16, 2012 the official Twitter API turned off RSS options per this article. What I wrote here doesn't work anymore.
I personally like keeping track of some Twitter accounts (especially security related ones) using Google Reader. Unfortunately, I've found lately though that Twitter keeps messing with RSS urls, and getting subscribed without errors can be hit and miss.
Here is my understanding of the current format as of this posting ...
If you have a Twitter account like @johnswayer that you want to follow in Google Reader. Then take the following main URL (twitter.com/statuses/user_timeline/) and add <twittername>+.rss -- for example:
"https://twitter.com/statuses/user_timeline/" + "johnhsawyer.rss"
Did I get this right? Did Twitter change this already? Is there a better way? Leave a comment or send me email and I'll update this post.