Googol is a calculator and search launcher for OS X that makes use of Google™'s internet search engine and on-line calculator functionality.
Note that the main work performed in this application is performed by Google™. The guys at Google™ have done all the work behind the scenes, and all credit is due to them. This application is a front end to the work they have done.
Using Googol is simple. Type an expression in the entry box. Then hit Return or click "Calculate" to perform the calculation.