tested on my unibody macbook pro
I had the same results as previous poster, it seems that the values showed up as 0 when I first installed it and the driver it requires and autoinstalls during first startup.
Then, I quit the coolbook app, reboot, ran it again, and viola, it shows the frequencies and volts.
Since I have no registration, I can't test it but I purchased it (the 2nd one I purchased so far, used my last reg. on my sister's Air) and am waiting for the license. I think he manually approves the registration stuff so it will take a few hours before I get my license to tweak and test.
I'll keep you all posted.