Square just announced Works with Square - a program that encourages partners to build accessories with the payment ecosystem. Griffin's Merchant Case + Square reader is the first iPhone case that incorporates the Square reader for swiping and storage positions.

The case stabilizes the Square reader when it's plugged into the iPhone's headphone jack and stows it in a recessed slot on the phone's back when not in use. Check it out here: [Griffin Technology, Square via The Verge]