untested by me but thrown in for discussion:
snip (unknown internet source)
... a neat utility called RM Clock can be used to undervolt the processor (Intel ior AMD). If you are a geek, it should be clear to you that this reduces power consumption and hence minimizes heating; if you are not a geek, or at least a semi-geek, don't try it - the utility has no user manual and you have to use some common sense and browse through their forum to get an idea how to set it up and running... A search in google using the "RM Clock" search string should bring it up.
BTW, this utility might be also of use for Intel/AMD based notebooks including CoreDuo. I personally use it on my Pentium M and I am pretty satisfied with the power savings it provides
un-snip
cheers
al