Modify the form attached to the "Site Members" list

Jan 19, 2009 at 8:14 PM
Could someone explain how I can modify the form used to manage users? 
I know it is linked directly to the list called "Site Members", but I wanted to change some of the fields around and modify the order in which we enter the data but I can't find where I can modify that form.
Thanks!
Zoltanar.