I'd suggest maybe getting a minidisc player. Some of them have microphone plugs or even mics attatched if you get a better model. You can buy a few tapes, I think they hold like 5 hours each, and they are extremely decent quality. We used them for production at my school (I went to school for film/video/media).
also belkin makes a portable 'voice recorder' for the iPod (regular, not mini), that claims to record hundreds of hours of voice recording, depending on the size of your iPod (gigs), but I'd be willing to bet the quality on a minidisc recorder would be much better.
hope this helps,
tricia.