BlogBridge : Blog and (RSS) feed aggregation
Free and open source - and it runs on Windows XP, Mac OS X and Linux. BlogBridge is a Java based RSS reader and aggregator that finds blog items based on keyword input and category topic. It caters for users who subscribe to a large number of RSS feeds and blogs, and helps organise feeds into guides and folders. Users can create SmartFeeds to filter feeds based on keywords, dates, ratings and other criteria, as well as create and share custom feed tags.
Tool suggested by Chris Smith of Shambles.net