This Saturday at 12:01 a.m. Facebook will be allowing users to select their name as part of the profile URL. This is great for SEO!!! Currently, Facebook URLs are made up of numbers and references in long strings which make it difficult for search engines to differentiate users with similar names, and difficult for you and I to share our Facebook profiles outside of Facebook. So if you are someone who wants to be found via search�the current URL structure makes that difficult. Being security savvy, Facebook will not allow those who have recently joined Facebook to select this option to prevent name squatters. And no worries, your old URLs will still work. Whether or not Fan pages will immediately have the same option of selecting vanity URLs is unclear.
Companies might be interested in going here: http://www.facebook.com/help/contact.php?show_form=username_rights to reserve their company name so that someone else cannot register the vanity URL.
For more information (and thanks to MG Siegler) you can visit Tech Crunch: http://www.techcrunch.com/2009/06/09/you-have-three-days-to-pick-your-facebook-vanity-url/
And if you are interested in learning more about search-friendly URLs my fellow bloggers on Oshyn.com have written many posts and some whitepapers you can download here: http://www.oshyn.com/resources/whitepapers.html