Google lets you search with your voice on your iPhone
It's interesting that Google is rolling out cool products like this for competing mobile devices like iPhone before their own, Android, but it does make sense. When you talk about getting rapid adoption, it doesn't make sense to target less popular devices first, even when one happens to be your own.
You can find the free Google application in the iPhone App Store. Once you've either installed this application for the first time, or had it updated, you are ready to start searching with your voice. Launch the application, put it to your ear, then speak your search query to give this feature a try. It's unclear how accurately it will translate voices into the correct words, but it's no secret that they have been working on this technology for a long time.
Google executives declined to estimate how often the service gets it right, but they said they believed it was easily accurate enough to be useful to people who wanted to avoid tapping out their queries on the iPhone’s touch-screen keyboard. -- New York Times
I would expect that an equivalent feature will be available for Android before too long.