When creating a randomly placed bunch of light probes I've seen stuff talk about interpolating character position between the lights on the cpu. But when I'm dealing with static geometry like walls, how do I have the pixel or vertex shader know which light probes to sample? What is the lookup method? And how are the light probes stored on the GPU?

Yea that was one I was talking about. I saw a demo where light probes were used to update light maps and after reading about enlighten's update, it sounds like they just update light maps as well.