Don't know too much about the pros and cons of each
Team Rankings
http://www.teamrankings.com/
RPI
http://realtimerpi.com/
KenPom
http://kenpom.com/
Sagarin (USA Today)
http://www.usatoday.com/sports/sagarin/bkt1011.htm
Dolphin
http://www.dolphinsim.com/ratings/ncaa_mbb/index_pred.html