The market for used iPhone's is fraught with risk, because you may end up paying hundreds of dollars for a locked off device, or worse -- one that appears legit but can't make calls. Apple has just revealed an iCloud tool to nip that in the bud by letting you check a device's activation lock status. All you'll need is the iPhone's IMEI or serial number. If you're the rightful owner, you'll get info on how to disable any activation locks before selling. If you're buying, you'll be shown how to remove the previous account (with the seller's cooperation). The tool will be particularly useful at sussing out "doulCi" devices, which bypass the iCloud to disable activation but won't actually connect to a cell network. Meaning you won't get fooled by a stolen or lost iPhone that appears to work, but is actually... an iPod.