The best sites that I have been able to take a look at.  This is were I get a lot of my information from.

http://www.marineaquariums.com/

http://www.geocities.com/RainForest/2298/

http://www.reefsource.com/troubleshooting.htm

http://ourworld.compuserve.com/homepages/wmckenzie/reef.htm

http://www.aquariumcamera.com/

http://www.petwhse.com/

http://www.mcs.net/~rogers/frame.html

http://members.nbci.com/einsteins12/aquaria/index.htm