To help me with my podcast I have bought a couple of microphones one lapel and another from Zoom
The itouch mic $13 US (which is a lapel mic for the iphone)
and a Zoom H4n (a bit over the top for podcasts perhaps but I’m also in a band so have used it to record demo tracks) $450
I have used them to record my latest podcast on my bands website www.jimmyyukka.com I used the iphone mic as a backup mic (which was just as well as the Zoom H4n filled up halfway through the recording).
My Opinion on the itouch mic
cheap and easy and sounds better than the iphone headset mic (worth the $30)
My Opinion on the ZoomH4n
Gorgeous as a portable recorder or an small a/d for my laptop it even has gates