GTweet.net pretty much says it all, but as a quick recap for those who don't know: I wrote a PHP application to allow people to read their Twitter feed in Google Reader.
It's currently in beta (and in need of a few good beta testers) but should be feature complete and reasonably reliable. Some of those features include the handling of Twitter authentication, displaying the tweeter's avatar in the RSS feed and the ability to reply to tweets or to favorite them from within Google Reader.
To be clear, favoriting or replying to a tweet opens a new browser window, but the links are provided below the text of each tweet for your convenience.
The service is completely free so why not give it a try? Visit http://www.gtweet.net to get started.