How do i add required field to registration

[geesh]

I am using the 4images gallery to power my templates site at http://www.geesh.com

I am not very fluent in php and need some help.  I need to change the registration process to make it required for users to give their homepage url upon registering.  Currently it is set as an optional field in their profile, and i want to require users to enter it during registration.

Anyone have an idea as to how i can do this?!