How to create your own category RSS feeds with Blogdigger (using blog id. and the subject prefix…precise stuff!)
This post goes further and runs the feeds through Feedburner:
NOTE: I have a del.icio.us version of this blog…I bookmark all my posts in their respective categories with del.icio.us tags. So if you want to subscribe to the RSS feed of just a category or even combine multiple categories please find them at del.icio.us/libraryclips.