Daniel Jalkut over at red-sweater has been doing tons of excellent detective and work around work on the MBP CPU whine issue that I believe all MBPs currently exhibit. My MBP has the whine at least. His most recent work around, the MagicNoiseKiller is an extremely classy work around that doesn't eat battery or cycles. Anyway, if you have a MBP, you will probably want to check this out. Enjoy!

Update: As Daniel noted in the comments, there is no real evidence that the the MagicNoiseKiller doesn't eat battery, but it seems as though it is at least a more efficient hack than the QuietMBP.