Not trying to start any fires here, but I too am getting two different temp readings for battery and CPU. I'm using one of P3's kernels and running FroYo.
It has gotten stuck at -40C/-40F for the CPU reading a couple of times, but a reboot fixed it. The temp does change, so I know it's not a constant reading. I know the original P3 kernel I had didn't even have the option to set the profile using CPU temp. Something is recording different temps.
Edit: I stand corrected. It stays at 28C. I just played a Flash game to get the temp up and I could feel the difference in temp, but the CPU reading is still the same. I must've been seeing a different temp when it was still set to battery temp. Thanks for bringing that to my attention.
Double edit: I don't know what caused it, but my CPU sensor readings seem to be working again. It got as high as 120+F (I was in the desert), and now it's reading at 77F. A few mins ago I was running Pandora and it was somewhere near 90+F. Nothing changed in my setup, but it appears to be working again. I say "appears" because it was my understanding these kernels cannot report CPU temps, but something is allowing the readout to change.