Mac Rumors reports that the Find my iPhone feature is free in iOS 4.2

The ability to remotely locate your iPhone is one of the most appreciated and sought-after features of Apple's MobileMe package. If you've been on a frantic Black Friday shopping spree, for example, and accidentally left your phone behind at an unknown store, you can quickly dial up Find my iPhone on your Mac to figure out where your errant smartphone is hiding.

Once you've upgraded your iPhone or iPad to iOS 4.2, however, you'll be able to use Find My iPhone for free with the iPhone 4, iPad, and 4th Gen iPod Touch.

  Find my iPhone to be free in iOS 4.2