The only one I'm currently aware of is "[Bitcoin Laundry][1]" operated by Mike Gogulski. They charge a 4.555% commission rate and do little more than accept a payment then re-send a payment. There is also (according to the [Wiki][2]) that the service is only lightly used and might not be adequate to provide any real anonymity. You might be better sending then withdrawing coins at Mt Gox with a decent delay between transactions - the sheer volume of Mt Gox's transactions as well as the size of their wallet would make them much more effective and there's nothing I'm aware of to stop you from creating an account with a throwaway email address and accessing Mt Gox through TOR/I2P/etc.


  [1]: https://web.archive.org/web/20160219173707/http://bitcoinlaundry.com/
  [2]: https://en.bitcoin.it/wiki/Bitcoin_Laundry