You must be logged in to edit subpages under the Users page. You can log in using your atitd.info account. For more information on setting up your atitd.info account, see: http://www.atitd.info/new_register.php
Feel free to create your own user page here and fill it with whatever information you want. To do so, just click on your login name in the upper right-hand corner of the page ("Logged in as: User"), then click on the "Edit text of this page" link at the bottom of your user page. When finished, click the "Save" button. For more information on editing wiki pages, see Formatting.