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".
In preliminary tests, the app recognized 8 out of 10 names from my contact list. Note that you need to say both the first and last name. The system then returns a list of the numbers for the target person (home, business, mobile); you choose one and the call is placed.
I am pretty sure that the results will vary from person to person; but if you are like me (and speak english in the same way i do), the app is a keeper.