ANT is a freeware video aggregator that lets you subscribe to RSS 2.0 feeds with video enclosures. The Beta software requires Mac OS x 10.3 Panther and uses web browser plugins to display video for QuickTime, Windows Media Player, RealPlayer, DivX and XVID. ANT can also play audio files making it suitable for podcasts. There’s a list of current features here and a FAQ page.
You can join the Beta Testers Yahoo! Group to learn more about ANT and its development.