The Internat Encyclopedia of Philosophy (http://www.utm.edu/research/iep/)
The School at Athens, by Raphael
(http://www.ecu.edu/cs-cas/classics/images/classchoolatathens.jpg)
Clickable version - find out who all those guys are! (http://un2sg4.unige.ch/athena/raphael/raf_ath4.html)