Just stumbled across this by accident – a video about an iPhone Mic called ‘Mikey‘:

View video – if embed doesn’t work

Not sure if it enables you to record great audio whilst recording video, or if it is just for audio. I do like the line in feature and the fact that you can charge it by USB power to stop it draining the iPhone’s battery. Hmm… I shall await the future release of the new Mikey and wait a while…