The latest update for the Google Mobile iPhone app has a very cool feature:  voice search.  You just open Google Mobile, lift the phone to your head and say what you want to find.  That’s it.  When I said “What is the latest book by Neal Stephenson?” I got:

Your iPhone knows where you are, so you can ask about places and events nearby, and Google Mobile will hook you up.

P.S.: To take screenshots on the iPhone, press the sleep/wake + home button.  The screen will flash to let you know it worked.