Fonix iSpeak is a voice activation application for the iPhone 3G. There are a couple of operations that you'll be able to accomplish just by speaking a command. You can dial someone by saying a phone number or the name of a person in your Contacts list. You'll also be to whiz through your music library, play a song, or start up a playlist by saying the name of an artist, song, or playlist.
According to Fonix Speech, Fonix iSpeak "includes a run-time engine that sits on the phone allowing users to interact with the personal contents of their Apple iPhone™. Unlike other voice applets that enable voice search of the Internet by sending commands over the airwaves, this client-side application gives users the power of voice interaction with their personal content and eliminates network latency."
There's no word on when the app will actually be available nor is there a price on the website, and the company didn't respond to a phone call. Fonix Speech says that they'll be selling it "directly" and through "traditional Apple distribution channels" -- the App Store, perhaps?