I was browsing through macosxhints and I came across this. Hopefully some of you will find it helpful.
When I first read it I was slightly worried because I assumed my new iBook would have the same problems because of the new powerbook-like trackpads but thankfully that doesn't seem to be the case (at least for now). kernel_task does not jump higher than 4% for me.
Yeah. If you read the link Terriyaki posted, it is in fact a firmware issue with the trackpad usb two finger scrolling that comes with the new 2005 powerbooks.
Kernel task seems to hover around 5.00-10.00 without any activity, which drains about 20-30 minutes of battery life. After I installed SideTrack 1.2 over the scrolling drivers in my powerbook, my kernel task now sits at a nice 0.5 - 1.00, which is a far cry from the stats I was getting before.
My battery life?
I'm running the projected 4.5 hours that is advertised by Apple.
Too bad it's $15 for SideTrack. But hell, I like this battery life improvement.