Pimp War

Pimp War is a great free, browser based online game. You can live out all your pimping fantasies here - work your pimp hand, make crack, hire goons, buy a sweet ride and all the other things that pimps do. Here's the full explanation from the site:

You will become a master at the art of pimping your hoes, commanding your thugs and battling your enemies to protect what you have and to help your empire grow. This game is NOT for whiners. PimpWar players have 5000 ways to call you a bitch ass. So if you think you can handle it we suggest you get a couple friends together so you are not alone in this bad bad place and then bring yo bad self.

It's highly addictive. Don't even get started if you're not ready for a commitment.