Help: Orbital Camera and Lighting

I'm working on a project, in which I've got a
camera that can orbit around models that I've
loaded. It does this using gluLookAt with some trigonometric calculations determining
the values of it's position and orientation.

I want to have a light that shines on my
scene equally from every position and
orientation -- that the lighting of the scene
doesn't change based on where I am, and covers all objects equally.

I've tried doing this before the camera is
placed, after the camera is placed,
and nested in matrix push/pops. I've yet to
get the desired effect.

Any help on this is appreciated.