How do I allow users to set a PW when they sign up for my WPMU site

On edublogs I see that you can create a UN and PW all on the sign up page. Even after I installed pro sites and other plugins for WPMU I still do not see this option. Is there a plugin that I am missing? Also I can’t see a way to edit the signup page to make it more streamlined and better designed? I don’t see it is my "pages" section.

Thank you,