The origin of the word Hooker (from Uncle John's Bathroom Reader):
"Although occasionally used before the Civil War, its widespread popularity can probably be traced to General Joseph Hooker, a Union soldier who was well-known for the liquor and whores in his camp. He was ultimately demoted, and Washington prostitutes were jokingly referred to as "Hooker's Division".
Given this origin, I personally don't have a problem with the word 'hooker'. But that's just me....
I do, however, prefer SP or escort. I actually don't mind the term call girl either but considering my bookings are usually done via e-mail, it doesn't really make sense to call myself that, lol.