Can a PowerBook or MacBook be configured to automatically wake when power is connected? I'm looking to turn an old Mac laptop into a "car-puter". However, I don't want to drain the battery on either the laptop or the car. Is there a way to configure it so that the computer automatically wakes up when plugged into power? (I know that it can be woken via ethernet, but I don't know how I can turn that to my advantage.)

My specific use case is a late-model PowerBook G4 running 10.5, but I'm also curious about whether this can be done with other models or OS versions. Thanks!
As you indicated, this does depend on the specifics of the hardware - but the pmset acwake command is used to read or change the intended wake on power change status for a Mac.

The man page for pmset goes into some detail how to use this command line tool to change settings.

I couldn't find a reference that calls out which models work with this setting - you may have to experiment or do some more research.