Of course, the obvious answer is to simply legalize and regulate prostitution in general. If a woman has a service she wants to offer, she can get licensed, tested regularly for STDs, verified for her age, and of course since she's putting herself in the 'market', she's generally going to be considered a willing participant and not a sex slave.
Agencies who provide services could likewise be regulated, licensed, subject to regulations and inspections, hold records for testing, signed contracts for the girls who work for them, verified documents proving age etc.
Men would be happier. Women would be happier. State and federal agencies would get more money from taxing since income can then be 'over the table', and licensing fees. Crime would go down as these acts wouldn't be illegal anymore. Police and law enforcement could then go after real criminals.
Sounds like win/win. Of course, it'll never happen because the religious right would scream bloody murder.