The JW FLV Media Player (built with Adobe’s Flash) is an easy and flexible way to add video and audio to your website. It supports playback of any format the Adobe Flash Player can handle (FLV, but also MP3, H264, SWF, JPG, PNG and GIF). It also supports RTMP and HTTP (Lighttpd) streaming, RSS, XSPF and ASX playlists, a wide range of flashvars (variables), an extensive javascript API and accessibility features.

More:
http://www.jeroenwijering.com/?item=JW_FLV_Media_Player

Demos:
http://home5.inet.tele.dk/nyboe/flash/mediaplayer/