Lately I have begun to get more and more annoyed with my feed reader. I use a simple feed reader which lack most features except for subscribing to and reading feeds. The one thing that annoys me the most is that it can't aggregate several feeds into one feed. Yesterday I finally decided to scratch that itch.
His method uses the Zend Framework to accomplish the goal - and "the whole website logic (both model and controller) is about 200 lines of code". There's no exception or error handling in it, but it works and the Zend_Feed module works well to grab just about any kind of feed.