The iPhone has replaced a lot of single use electronic gadgets, but if you want to make a decent audio recording, the phone's little mono microphone won't exactly rival a decent separate recorder. This snap-on microphone fixes that problem.
Last year we saw the Blue Mikey, which works great if you have an iPod, but isn't compatible with the iPhone 4. Then there was that Fostex gizmo which looked good for shooting serious video with quality audio, but was also kind of clunky and expensive.
The new iM2 from Tascam looks like it has all the right features, with stereo recording compatible with all recent iDevices, a nice compact form factor, and a price that's probably cheaper than the ticket to the Coldplay concert you're trying to bootleg. It can handle volume levels up to 125dB, so even AC/DC shouldn't be able to make it distort.
The Tascam iM2 is available now for $80.