I have never used the bitcoinvanitygen service and cannot vouch for it, but the website says it's free. If you try it I'm interested in hearing how good it is.
http://bitcoinvanitygen.com/I'm trying it out. I'm currently on the queue.
Though the limits are pretty low. Only 5 letters vanity and 6 for no case sensitive.
The limits are always low except if you put some money or hardware into it. Be careful who you trust for creating your vanity address.