Not sure if this is new to Beta 4, or if it appeared earlier in iPhone 3.0, but it's the first we've seen of it so we're passing it along. What is it exactly? Simply go to Contacts, pick a name, and then swipe to call up the red "Delete" button that we all know and love from Email and other, previous apps going all the way back to iPhone 1.x.
Nice way to speed up removing unwanted or outdated information. Thanks Apple!
(And thanks Adam for the tip!)