Audio-only sharing hasn't taken off for the constantly-connected iPhone crowd, though, and neither has using your phone for any kind of serious sound recording. Journalists and musicians alike suffer dodgy inferior recording quality on a daily basis. All the potential is there, though, apart from one crucial element -- the microphone.
RODEs iXY is a smart solution to this. With a cross-set stereo microphone (that's the X/Y in iXY) and a miniaturised analog-digital converter, the iXY plugs into the bottom of your iPhone -- currently the iPhone 4 and 4S, as well as the iPod touch (4th generation), iPad, iPad 2, and iPad 3 are supported.
Clip the iXY into the iPhone's 30-pin dock connector, load up the RODE Rec app (free on the App Store), and you're set. The iXY can record at resolutions up to 24-bit/96KHz, far in excess of what the iPhone's mediocre integrated mic can handle.
Being a proper 90-degree-aligned microphone pair, the iXY claims to record near-perfect stereo audio. The iXY also comes with a pop-sock to cut out interviewees' accidental plosives and any intrusive wind noise.
The RODE Rec app is just as smart as the iXY. You can use it to adjust the input levels of your recording, play back what you've already captured, insert markers and get rid of any accidental tracks.