The past couple of times I've met with Intel, they were running a neat little widget on their test machines, that showed the processor and level of Turbo being used. It's simple, but cool. The company has just released it (finally) to the public, so if you have a Core i5 or i7 processor, you can use it just fine:
http://www.intel.com/support/processors/sb/CS-031038.htm
http://www.intel.com/support/processors/sb/CS-031038.htm