I'm embarrassed to say I've read most of them! 
Heres a few more, either ones I've read or waiting to read.
Straight Up and Dirty by Stephanie Klein
Around the World in 80 Dates (not sure its really erotic, but sort of I guess)
L:yn A Story of Prostitution by June Levine and Lyn Madden
Call me Elizabeth by Dawn Annandale (one of my favourites)
Swings: True Confessions from Today's Swinging Scene by Ashley Lister
Sex Fantasies by Women, for Women
A Serial Shagger's Guide to Internet Dating by Clive Worth (this guy is sooooo big headed its amazing!)
Call Girl by Jenny Angell
Madam by Jenny Angell
Girl with a One Track Mind by Abby Lee
The Butcher, The Baker the Candlestick Maker by Suzanne Portnoy
Girll in High Heels byu Ellouise Moore
e-luv an internet romance by Dave roberts
Diaries of an Internet Lover by Dawn Porter
gigolo by Golden
Millions of Women are waiting to Meet you by Sean Thomas
I don't just read this type of book honest!! 