Set up a calculation expression. THe field can be text with an auto-entered expression or a calculation field that returns text:
If ( Not IsEmpty ( YourContainerField ) ; "yes" ; "no" )
Then format your field as a radio button with the values "yes" and "no". If you use auto-enter, make sure to clear the "do not replace existing value" check box.
Well that was awesome! Thanks so much.