You can get free motion capture files from http://freemotionfiles.blogspot.com/2008/12/dance-bip-motion-capture.html link They are in .bip file format and they work fine with max 2008, and I'm sure they will work fine with older versions of Max and Character Studio too. I did a rough test as you can see in the video above :)
The files available are:
* Ballet Dance
* Cat Walk
* Dance
* Dance Hip Shake
* Dance Hop to Stop
* Night Club
Have fun!
Update 25 September 2009, it seesm the above link doesnt work anymore, so its best to go to the root of the page and search from there: http://freemotionfiles.blogspot.com/