From Transom.org — review of two “microphones” for iPod/iPhone for quality recording.

iPhones, iPods and other portable media players have included recording utility applications for several years, but there haven’t been good ways to connect a high-quality microphone as an input. Even if one could, the rest of the input circuitry was less than ideal, often resulting in noisy, grainy or distorted recordings. Additionally, these devices often recorded at unacceptably low quality. Some of these devices have been able to record at high sample rates and bit-depths for some time, but getting a good quality signal INTO the machine has been a challenge.

But now, a few different approaches have presented solutions for recording onto an iPod. The first is the simplest: a high-quality microphone that attaches to the dock connector on most iPods and iPhones. There have been several such devices on the market previously, but the Blue Mikey from Blue Microphones represents a significant advance in quality. The second approach is more elaborate: an add-on accessory case that connects to an iPod, and provides two built-in microphones, as well as professional-quality XLR inputs for using external microphones. There are two devices that use this second model: the Alesis Pro Track, and the Belkin GoStudio. ….