I've just updated my Deface face detection library to take advantage of Flash 10's Vector class. This has resulted in a 20 - 30 percent speedup. See a brief example on my site:

http://cosmodro.me/blog/2009/jan/11/deface-flash-10/

and the google code page:
http://code.google.com/p/deface

If anyone has a webcam and the demo does NOT work, please let me know. As always, if you are interested in submitting an optimization patch, or otherwise contributing please contact me.