In my WordPress based site, I want to add a custom field (e.g. type of user - employee, investor) in the user registration form in the **admin side**, **without editing the core file**. Can anyone please suggest how can I do it, may be a plug-in or some script? 

I have already tried Cimi, Register Plus, CYC plug-ins but they all give facility to add custom field from front side registration form OR in the user edit form after the user is registered for first time from admin side. Is there any way we can do it in the user register form from admin side?