is there a way to add more fields to the registration form

Is there a way to add more fields to the registration form. I need to capture more data during sign up.

Also, the css for the registration page looks broken. I have this plugin installed on another site and it works fine. On this site when i get to the completed registration process where it shows the list of plans, the paypal button is sitting right next to almost on top of the plan names and the table structure is no longer there.