Windows utility to alter FSB of Core (2) Duo Motherboards?

Is there a Windows program that can alter the FSB of a Core Duo or Core 2 Duo motherboard? I seem to recall that Aopen provide a utility that allows this with their 975X based Core Duo board, so I’m wondering if there’s a generic solution that supports Intel chipsets.

I’m aware that Clockgen can do this, but only for a limited number of compatible boards. I’m wondering what other utilities are available that also do this.

Since I want to under-clock as well as over-clock the FSB I'm wondering what the lower limit will be. 800 shouldn't be a problem for desktop boards as some chips use that anyway; is 667 going to be possible with the desktop chipsets (965)?

Thanks. So 667 should be possible on a board that supports changing the FSB in 1 MHz increments. And the 975X only officially supports 800/1066 but is used in the Aopen board with Yonah at 667.

I don’t want a remote control, but software that can set the FSB. Preferably, software that will set the FSB as you launch it, so that you don’t have to interact with it. i.e. it remembers the last settings that you used and sets to those values on execution.