Sorry to resurrect such an old topic... but does anyone have the pictures or an exact location on the heatsink to clip the fan to? I was curious to do this myself with my G5 here but I can't seem to figure out how to exactly clip it. help?
again, very sorry to resurrect an old topic.
EDIT OF EDIT: This is the newer Intel stock fan that comes with the 45nm Core 2 Duo CPUs and I believe everything from the middle of 2008. See how the clips are built into the fan and how much smaller it is.

DOUBLE EDIT: I figured it out. I needed the OLDER Intel fan. I got one from a PC I was fixing for someone (was on a Celeron D 2.8GHz), cleaned it up and popped it on. it works great! here comes a pic.

it generally spins at about 2200 RPM at maximum. the old Shuttle fan was put onto the back as the pull fan at LOW speed, not ultra low and not medium. smart fan is overdoing it. it makes a constant buzz but nothing that most people can't get used to. I also recommend getting rid of the horrid honeycomb grille, as has been stated in the past.