According to Apple, MobileMe Find My iPhone can help an iPhoner protect info on a missing iPhone by remotely assigning a 4 digit passcode lock, a new feature that comes with iPhone OS 3.1 software update.

Apparently this new feature is especially useful if you haven’t set an iPhone passcode previously or if you require a new passcode.

The process is fairly simple, first install iPhone OS 3.1 update then log into your MobileMe account, next hit Find My iPhone in the left hand column and then hit Remote Lock, and job done.