My colleagues and I at iPhone Life have written about the OlloClip several times, and it's a great clip-on accessory that adds different lenses for your iPhone camera. The fatal flaw, however, has been that it requires a naked iPhone, and I like to keep my iPhone in a case.
They include an insert for an iPod touch, as well. Also in the box is a slip-on mount for a tripod, in either landscape or portrait model, which is a nice touch.
Photography on the iPhone has come a long way from the early days and OlloClip is one of the reasons. Now, with the Quick-Flip case, it's easier to get your OlloClip on your iPhone, and take great shots. And the case itself is nice and slim, and available in multiple colors to match your iPhone!