Adding new field in user profile

Hi All,

I am working on Drupal 6.0. I have enabled my profile module and done all settings. Now, in the profile page from where we add fields in user profile, listing seven fields which are

single-line textfield
multi-line textfield
checkbox
list selection
freeform list
URL
date

Now, I want one more field i.e. radio field in the above list. So, may anyone help me to doing such modification. I am unable to do this since I am completely new in both i.e. Drupal and PHP.

Thanks