Facebook Fan Page Custom URL
To change the URL name of your Facebook Fan Page, follow these steps:
1. Go to http://facebook.com/username
2. If you’ve already changed your personal url, there will be a yellow box that says so. Underneath that, it says Set Username for Pages. Click there.
3. There will be a drop down menu of all the pages you administer. Pick one and click Check Availability.
4. Make sure you are sure about this change, you can’t redo it later.