CosmoPod

CosmoPod is a Safari add-on that helps you download and convert Flash, DivX, WMV, and Real Media videos from the Internet to your Mac, iPod, iPhone, or AppleTV automatically.

It lounges in Safari's address bar and activates whenever a video is detected on the website you're on. In a single click, the video is downloaded and converted to a friendly video format, and added to your iTunes Library so it's ready for your next iPod / iPhone / AppleTV sync.