Disable Turbo Boost on Core i7 Mac?

Is there any way to programmatically disable Turbo Boost on a Core i7 mac running Mac OS X ? I need to be able to do this for benchmarking purposes during code optimisation etc. Failing that, any kind of utility which can disable/enable Turbo Boost, even if it requires a reboot, would be useful.

There is a related question (not Mac-specific) on SO: How to turn off Turbo Boost temporarily? but even for PCs it seems that there may be no way to do this programatically/on-the-fly ?