A couple of suggestions posted here are incorrect - or slightly misleading...
The Popwire Components, while Universal, do nothing for web-delivered content. The UB of Popwire has worked perfectly for local WMV files since it's release.
The Flip4Mac components have never been "private beta releases." Both of the UB versions of the F4M components were open to everyone for testing on their site for a limited period. Both 2.10.24 and the latest (more optimized for intel) 2.1.0.29 release were available free and open for a 24-36 hour period, and several people posted that information on this forum at that time.
VLC, while a terrific open-source video client, is useless against the very popular earlier WMV3 codec.
Across two intel Macs at home and various others at work, I've not seen a situation where WMP9 is necessary any longer.