Would anyone know how to create a UDF that resides within a VFP 6.0 Form that can then be called by an 'OnKeyLabel' statement?

You mean a custom method?

From the form menu select new methos and give it a descriptive name. Then write your code in that method.

Set the form's KeyPreview Property to .T.

Then, code like this in your new custom method:

*** You can look up ascii values in the help topic for INKEY()
IF nKeyCode = << ascii value of whatever key you want>>
  Thisform.MyNewCustomMethod()
ENDIF