Drupal 6 CCK - Having a textbox appear when 'Other' is selected

I have a special content-type that I have created, and one of the fields is a radio button list. The last element is named 'Other' and I would like to have a textbox appear and allow the user to enter in a non-defined value.

Is this sort of capability provided by any sort of module, or is th开发者_Python百科is something that needs to be coded by hand? (If so, would you mind pointing me in the correct direction?)

The CCK Select Other module appears to get you most of the way there. I imagine it could be modified to work with radios fairly easily.