SMC Monitor is a Java front end for the command line tool smc by devnull. The app was written by el coniglio.
Download: SMC Monitor.zip
In the preferences window you can define which SMC keys should be shown in the main window, edit their descriptions and set the conversion type.
There’s also a window with P and C states info parsed from ioreg.
You need this new version of FakeSMC and its plugins to have more keys available, such as CPU frequency and voltage (IntelCPUMonitor)