Update: June 2013: Previously, this post contained information about how to access RSS feeds of Twitter user timelines so that you could read them in whatever RSS reader you wanted to. But now, those RSS feeds are completely deleted because Twitter is evil. However, it is still possible to recreate the RSS feeds if you jump through some hoops. Probably the easiest way is described in this blog post. It'll take a couple minutes to set up, but then you can easily get an RSS feed for any Twitter timeline.