Talk and ye shall receive, or something like that. It seems that Google is launching a voice initiated search utility for the iPhone.
The little app that should appear soon in the iPhone's appstore will take your speech, send it to Google for interpretation and then send you back the same tangle of half-hits you currently get from typing in your searches.
Read more here.
By using a way to distinguish between voice and keyboard input by using the phone's accelerometer and proximity sensors, it can tell when you have the phone at the side of your head, similar to how the Iphone screen switches off when you're in a call.
Instead of interpreting your voice on-the-fly using the Iphone hardware, a recording of the voice query is sent to Google's servers for interpretation, sending back results "seconds later".
The search results will include local information when relevant, taking advantage of the in-built Iphone AGPS that lets it determine its own location.