Just thought you guys might be interested in this site. It shows angelfish that have been bred in captivity and the babies. Also, assuming the author of the site is right, the male angelfish are bigger and more colorful than the females. Obviously though, you cannot tell with an individual specimen because you need a second angelfish for comparison.
http://www.rcthawaii.com/angel/6.htm
http://www.rcthawaii.com/angel/6.htm
