Melodis Voice Dialer, from Melodis, works well enough, but unfortunately, it's not enough. The app store features quite a few voice dialers, and this one does not stand out in any way. The free vlingo, for example, dials by contact name and will also search Google and Yahoo, among other functions.
iPhone and iPad apps tagged "voice dialer."
To Call Vocalia a One-Trick Pony is an Insult to Ponies Everywhere
You might be tempted to refer to Vocalia, a voice-recognition app from Creaceed, as a one-trick pony, but why insult the poor little pony who has never done you any wrong?
The idea behind Vocalia is that with a modicum of training, you can pull up the contact info of anyone on your contact list by speaking his or her name.
"Say Who" You Talk it Dials
Say Who - Dialer is the voice recognition dialing app by developer Excuse Me Services, Inc. Available in the US, UK, Canada, Australia and New Zealand, Say Who lets you speak a contact name into the iPhone's microphone and then automatically dials the correlating number in your contacts.
Speech Cloud Voice Dialer Works Suprisingly Well
Speech Cloud is a free app by Massachusets based Adela Voice that allows you to quickly dial a number simply by speaking into the iPhone microphone, and saying (for example): "Call Clark Landry".