Late 2008 MacBook Pro no longer wakes up on its own Plain and simple here: about one week ago, my MacBook Pro stopped adhering to its wake schedule. I have had it set to wake every weekday at 6 a.m. for as long as I can remember. It has done so with 100% reliability as long as a power source is plugged in and the lid is open. Then it stopped. I finally went and checked the power savings pref pane this morning, and all is right with the world. I tweak my computer all the time, but have not done anything with this setting, nor have I installed anything that was advertised to affect power management. That being said, should I reset the SMC? This doesn't really seem to fall under what apple would normally recommend this for. 

Cheers
This could be related to the SMC or the PRAM. The System Management Controller controls everything related to power on your Mac. I would reset this first, and then reset the PRAM right after. Let us know if that works. You may have to reset the sleep schedule after resetting the PRAM.