There’s a bunch of surprisingly good voice recognition applications which are now available on the iPhone or iPod touch.
I use “Say Who” (free) for being able to do voice dialing, and “Say Where” (free) for using your voice to interact with Google Maps.
Google themelves just released a new version of their “Google Mobile App” (free), which enables you to use your voice in order to submit queries to the Google search engine.
Here’s a video showing how it works:
I love my iPhone more every day 
