The microphones built into iDevices are...okay at best. They're perfectly suitable for capturing your personal memos, but not exactly something you'd use to record live music or interview someone with. The iXY mic by RØDE aims to solve that problem, at least for iDevices with a 30-pin connector (sorry, Lightning users). It can capture up to 24-bit/96k-resolution stereo audio as long as you're recording with their app or its free companion.

The only downside at the moment is that they're currently sold out of these mics on the online store, but you can head over to this page and click the "EMAIL ME" link to be notified when they're back in stock. You can also see if any local stores are carrying it.