I've used wp-o-matic running cron jobs and was absolutely crazy over that great functioning plugin, but very disappointed when it had not updated since wp 2.6 and finally stopped working with the latest versions of wordpress.
RSS Poster has great potential, as NO ONE that I have tried works with wp 3.0 or 3.01 and there is much usefulness for it.
I tried RSS Poster Free version with 5 different feeds that open my news reader just fine when clicked in my browser address bar. RSS Poster free version does not work even after a reinstall. I really wish it did! I would probably purchase the full version for the cron fetching if the free version even worked.