[support] Profile Module Conditional Fields

I am designing a user registration form using the core profiles module in Drupal 6. I have been trying to search for a way to make certain fields appear in the user registration page based on the value selected in another field. For example, I have a select list called college name and if 'others' value is selected in the college name i want another field to appear which lets you specify the college name and moreover adds it to the list of colleges. I am just wondering if there's any built in module for this (conditional fields module doesnt extend the select list) or I will have to tinker with the code. Thanks alot!!!