We've seen a sharp uptick over the past couple of months in iPhone-related security devices, and Cobra's new Tag ($60, previously known as PhoneTag) is another iteration on the theme: a keychain- or bag-ready Bluetooth accessory that can alert you to loss or theft if the accessory and device move too far out of each others' range. The primary purpose is to let an iPhone user find a keychain or bag; using a free application, you can make the Tag accessory…
