I tried the application from:
http://macbricol.free.fr/coreduotemp/
However, the CPU temp constantly jumps betwee 28C and 34C. Always 28C and 34C. Never shows anything else, despite time or CPU load.
The frequencies seem to work fine, however. I've seen values from 1333 to 1667, but most of the time, it's on 1500 (I have a 1.83 MBP).
I have rebooted (not that I should have to) but I've never seen a reading higher than 34C and I know that even the outside of my case is hotter than that.
My MBP is week 12. Perhaps the application doesn't work on all MBPs?
Neither the people who did CoreDuoTemp or the Increw people seem to have any means of support...