Try the code sample: https://github.com/google/search-samples/tree/master/search-action and learn more at http://developer.android.com/guide/components/intents-common.html#Search
If you’d like to explore recent advances in speach recognition technology, also check out “Behind the Mic: The Science of Talking with Computers”: https://www.youtube.com/watch?v=yxxRAHVtafI