Are there any programs available for monitoring and measuring GPU temperature? I'd prefer something free, and for either Windows XP or Windows 7.
From the makers of CPU-Z: HWMonitor. Small, free, and can measure video card GPU temperatures.
If it's a Dell Precision, an excellent utility is the Dell fan control utility. It's got tray icons, graphs, manual and automatic fan speed adjustments, ...
SpeedFan monitors hardware and can read values such as temperatures, fan speeds, voltages, etc.