"In case if you don't know there is a hidden list named "User Information List" which displays all the users of the site (collection) {MOSS / Sharepoint 2007}. And there is a page "Simple.aspx"  which show this list, the URL for the page would be http://YOURSITENAME/_catalogs/users/simple.aspx."

Gregory S. MacBeth : User Profiles

Read the complete post at http://www.plijnaer.nl/weblog/2008/03/hidden-list-named-information-list.html