There are several threads on here reference sunfish ID... The most commonly referred to one is in the archives section:

http://www.pondboss.com/forums/ubbthreads.php?ubb=showflat&Number=92482#Post92482

Also, look at the beginning of this thread. It dates back a couple years with tons of pictures and what people think each fish is...

I will say this, sunfish ID for a person who isn't familiar with them can be very tough. Even I have to slow down and take a closer look every now and then. Throw in the fact that sunfish often hybridize in ponds naturally and you really can get your head spinning! Often times you know what species are in the pond, so guesstimating the hybrid is easier...