One of the biggest missing features on the iPhone is voice dialing. But with the app store, this missing feature is now available, and unlike many needed applications this one is free. The cactus voice dialer for the iPhone allows you to call any contact in your address book by using simple voice commands like "Call Bob Mobile". NO training is needed - the voice recognition software is based PocketSphinx which can recognize language directly.

It also has some nice customization features that allow you to do things like set a default number for the voice dialing of a contact so that you can get by with saying fewer words.