Step #1: figure out how to get Linux back. A recent upgrade of OS X had wiped the boot sector.
That did it. (note to self)
Then did some yabootconfig/ybin/etc stuff that should make it automatic now. We'll see.
Anyway, for the short, scary period I was in OS X without Debian, I accidentally clicked this big green box in iChat and I started talking to sherm over my laptop's speaker and microphone. I don't even know where the microphone is.... I can't see it anywhere! So yeah, Apple rules. Too bad OS X is so fucking slow. "Optimizing your system" my ass.
I come back in Debian and everything's zippy. Awwww.... what a relaxing feeling.