MiniDV is a 'newish' format that was introduced to replace the old Hi8 and associated media used in old camcorders.
Basically Hi8 etc, were minaturised versions of VHS tape you have in your VCR. VHS tape is analog. It's also crap/superseded by DVD
MiniDV is still magnetic tape BUT the signal encoded is in digital rather than analog format, hence the MiniDV tapes are capable of relatively high quality video recordings, even broadcast quality. But the thing is, the quality depends not on the tape, but on the camcorder.
Advice, buy the most expensive you can afford. Buy one with 3 CCDs. Don't buy w/out stringent research. Don't buy from Harvey Norman or other super-retailers in general based on a salesperson's advice.
Despite the hype over DVD recording camcorders, it's not hyped that many only record 1/2 an hour vs MiniDV's 180+ minutes. There's also hype over the min-mini-dv camcorders such as from sony, although they allow smallish camcorder bodies and they're new, these use mpeg-4 video format which I strongly suspect can't match MiniDV for quality.
Msg me if you have any other queries.
Also, if you're serious about using it for fun, as opposed to weddings and such that never get watched, I would also start saving money for a home editing kit and tripod. I can't emphasise how much better they complement your ambitous film-making experience.