Voice search is improving all the time, and Google brings the best we've seen to date. Its stellar iPhone app uses the accelerometer to activate search. When you hear a beep after lifting the phone to your ear, start speaking your search term. The accuracy of the listening software combined with the newly added MyLocation feature brings (mostly) spot-on search results that are localized to your whereabouts. As with versions of the Google Mobile App on other mobile platforms, this one also includes a tab of shortcuts to other Google services, including Talk, Reader, News, and Photos (Picasa Web).
While the search app performs nearly error-free, some people are disappointed that Google Mobile App doesn't hook into your iPhone's address book to voice dial your contacts. With voice processing so good, you, too, will want to turn over all your voice-triggered tasks to Google's software.