Ron Jeremy was also in "Spun" great and original underrated movie.
He's a bartender in a strip-club.
http://www.imdb.com/title/tt0283003/fullcredits

Nina Hartley is also in "Boogie Nights", imo best movie about porn's world.

I remember also Brianna Banks and Jessica Drake in "Sin" (crap movie, i seen only first 10 minutes), playing porn actress, so wasnt a big deal for them.
http://www.imdb.com/title/tt0307466/fullcredits