Underlying technique of Android's FaceDetector

I Found a couple of links too...Not sure if it would help you...

http://code.google.com/p/android-playground-erdao/source/browse/#svn/trunk/SnapFace

http://code.google.com/p/jjil/

http://benosteen.wordpress.com/2010/03/03/face-recognition-much-easier-than-expected/

I'm on a phone, so can't respond extensively, but Google keywords "neven vision algorithm" pull up some useful papers...

Also, US patent 6222939 is related.

Possibly also some of the links on http://peterwilliams97.blogspot.com/2008/09/google-picasa-to-have-face-recognition.html might be handy...