TempStat - Widget displays values of Mac temperature sensors
Version: 2.0TempStat lets you view the current values of the many Temperature Sensors found in recent Macs. It supports all G5 systems, G4 Powerbooks (greater than 867), G4 iBooks and MDD G4's.
Operating System: Mac OS X
In addition to Temperature readings, TempStat can show you the current speeds of the fans in your system.
Note: Support for Intel iMacs and various G3's and early G4's will be added in the next release.