The long way is to go into the power settings for the proc and see what it is currently showing. If you have it in auto mode it will show what it is running at that time. Not aware of a program that shows it on the toolbar.
There is the stuff thats included with Xcpuscaler... but I dont particularily like those oc utilities. I have nothing against overclocking... I really enjoy overclocking actually and its dangerous for me to have it avalible.