The folks at Makayama have created an application that adds voice activated dialing of contacts, as well as launching bookmarks in Safari or any other installed application. You must have a jailbroken iPhone in order to use VoiceDial because you must run the installer application to install it on your phone.

From the developers:

“Record voice samples for any contact in the addressbook. Just speak to dial the number. Open any application with your voice. So you can check your emails or start Google Maps by just saying it. And you can even surf to your favourite websites by assigning voice tags to your Safari bookmarks.The software uses a modern speech recognition algorithm which gives excellent results in real life situations.

The software works with all languages. It does not depend on a dictionary or vocabulary, but it stores your speech samples and links them to contacts, applications or bookmarks. When you’re on the go, VoiceDial lets you keep in touch even when your hands are full. It’s as easy as saying, “John Smith” or “Mail”. And you’ll be automatically notified of free updates via Installer.”

You can download a fully functioning demo of Voicedial or purchase it for $27.95.