Add modal functionality to existing login/registration system

We have an existing login/registration system that we are looking at adding modal/pop-up functionality. Specifically, require: 1) the login, change password and resend activation email forms to be opened in separate modal windows; 2) modal windows to be used is colorbox; 3) the forms to open in the middle of the screen, and only one form can be opened at a time. I will provide a copy of the login/registration pages to the winning freelancer.