switching from kdm to gdm

[stan]

I have a machine that was originally installed as Kubuntu, that I want to
use gdm as the login manager on. I have installed gdm, but i don't recall being
prompted for which one to use.

I think I should be able to change this using update-alternatives, but I
can't find out what it is called. Can anyone give me a clue?

-- 
One of the main causes of the fall of the roman empire was that, lacking
zero, they had no way to indicate successful termination of their C
programs.