Hi - I have been doing research on this for my own use and have come up with the following information so far;
1. There are too many 3rd party recording apps to mention - this link was interesting - http://www.everythingicafe.com/how-to-use-an-iphone-as-a-microphone/2012/04/10/
2. You can use the audio jack for a microphone device that has a triple ring configuration - here is a link for a converter - http://www.musiciansfriend.com/accessories/peterson-3.5mm--1-4in-iphone-itouch-a dapter-cable?src=3WWRWXGP
3. The iPhone 5 uses a lightning connector - since the Apple cable has an authentication chip, 3rd party providers have been slow in producing compatible devices - this is why Apple came out with a 30 pin to lightning cable and a 30 pin tp lightning adapter - so if you plan to try a 30 pin device with the adapter, I would suggest that you check the return policies on all purchases because there have been several reports that the 30 pin devices won't work with the adapters and the iPhone 5.