I thought this trick was very well known but a hobbyist friend of mine had never heard it so I figured I would post.
If you are thinking of booking a pse and are wondering what she looks like in non-professional shots, Ebay is actually a good source.  If you go to the homepage (not the mature audiences section) and type in names like Ava Devine, Lezley Zen, Sarah Blake etc you see photos taken at AVN and other conventions that are not enhanced.  I have used this to decide who to book.

My guess is those photos on Ebay were taken from http://www.fobpro.com/  This is THE source for candid photos taken at every adult convention... Glamourcon, Internext, Importnights, etc. are all there...

that is a great link, thanks Eddie.