MIT's Address Browser provides an speech recognition interface to Google maps.  From the site:

The AddressBrowser is a prototype speech-based interface that allows users to speak any city or address in the United States. You can say any valid address that follows a simple pattern, e.g., 32 Vassar Street in Cambridge, Massachusetts, the intersection of Main Street and Vassar Street in Cambridge, Massachusetts, or just Cambridge, Massachusetts.
In order to be heard you will need a microphone connected to your computer.

• Press and hold the big green button and say your address. The button will turn red when it is recording your voice. Just speak your address naturally. Release the button after you have finished talking.
• ...

It seems like it uses a Java Applet client front-end and a back-end speech recognition server.