Room for Debate tackles the question. Max Waltman proposes legalizing the selling but not the buying of sex:
Not to be bought and sold for sex should be a human right. Sweden effectively recognized this in 1999, criminalizing buying sex and decriminalizing being in prostitution. This law has been adopted in full by Norway and Iceland, partly in Korea, Finland, Israel and the United Kingdom. France may enact it.
The Dish 