Now you can download Voice Actions (via the Voice Search app) to control your Android phone just by speaking to it.
After installing, to start using Voice Actions on your Android Phone, tap the microphone button on the Google search box on your home screen, or press down for a few seconds on the physical search button on your phone. This will activate the “Speak Now” screen. Now see this video below to see the awesome things you can do with Voice actions.
Voice Actions for Android will let you control your phone using your voice to call contacts and businesses, send messages, browse the web, listen to music, send email, browse maps, search google, write notes and complete common tasks easily.
To Get Voice Actions for Android, simply download the Voice Search app, featuring Voice Actions. Voice Actions requires Android 2.2 (Froyo) and higher.