ericIf you’re at all interested in where video and audio for the web is going, this chapter by Mark Pilgrim is required reading. Mark does a great job providing background on the core cross-platform codecs that are in use today (with the cross-platform bit ruling out WMV) and talks about how HTML5 will offer native support for video playback.
His focus is primarily on h.264 and Ogg video, since offering video in those two formats will cover all modern browsers. He also describes methods and tools you can use to encode your videos in those formats (including Firefogg, which was new to me, and FFMPEG2Theora for Ogg, and Handbrake for h.264).
alex