Question for Audio Gurus

I want to create a portable podcasting rig, something I can carry in my hands or on my bike and travel around with easily.

It looks like the something like an iRiver or a Muvo would be fine for my purposes: both can record, both have enough “disk space” to record lots of audio, and both are quite small.

The Muvo seems to have the edge, especially when used with a Mac, because it just mounts as a drive on the desktop, and files can be copied to and from it, while the iRiver requires using proprietary software to do this.

But both seem to accept audio input only through a “line in” jack rather than a “microphone” jack, which leads me to believe that I would run into troubles if I just plugged a regular old microphone into them.

Can anyone (a) confirm that this is true or not and (b) if it is true, what can I do about it (preferably by some mechanism that doesn’t involve another piece of heavy equipment). Bonus points if you can do this without trying to explain to me how impedance, resistance and balancing work, and without using the abbreviation “dB.”