Spoiler Alert!!
Unified contacts (multiple version of same contact under ONE name), FaceTime tricks (switch that front/back camera), and Spoken books (turn your ebook into an audio book).
Read article here: From the Desk of David Pogue – Three Unknown Features of the iPhone 4 – NYTimes.com

Our first voice command? “Wash our dirty underwear.” It worked! Android is so cool.
Read article here: Voice Actions for Android