We've mentioned managing power a couple times here on the blog, including a brief introduction and a detailed step-by-step walk through by Alan Burchill (shows how to configure power options that consider Business Hours vs . Off Hours using Group Policy Preferences targeting). Here's a high level discussion of GP Preferences and why managing power using GPP will save money, time, and energy in a TechEd Online video.
Note: there's a bit of pre and post conversation chiat chat between Alan and I about my trip to Australia, so avoid it by skipping ahead to the 2:15 mark and stop at about 6:00.
The TechEd Online link is here:
LiliaG, Group Policy PM, @superlilia