This plugin allows your users to change their own profile url to http://www.domain.com/[profile_name] (without the [ ])
Upon installation, [profile_name] will default to the users' usernames, but they will be allowed to change it (!!!)
Admin can edit which [profile_name] is not usable, like "administrator" or "admin"
You can even edit profileurl_redirect.php and use it as your default 404 handling file
More information on editing your .htaccess file (for Apache servers) or custom error handling (for Windows IIS):

http://mike.simbunch.com.