Program to wake laptop from sleep when it gets AC power?

[CaseyBlackburn]

I've got an idea in my head of using a laptop in my car for media reasons. I'll be using a power inverter to power the laptop, and it will turn off while the ignition is off. I want the laptop to sleep when it loses AC power, and then I want it to wake when the AC power is restored. I can get it to go to sleep mode no problem. I just have no clue how to get it to wake up. Is there any software that could do this?