Initially, Facebook only allowed you to create a single personal URL for your username. Now, if your Facebook fan page for your business is established and has a growing fan base then you can easily create a personal (business) vanity URL for your business Facebook page. You need to be logged into your Facebook account.
If you have at least 25 fans on your page, you can set a custom username/URL
WASHINGTON, DC – Forty-five minutes ago, Facebook began allowing those underprivileged people like me to grab their personal URL or vanity URL on Facebook.