The 1st Gen actually does have mic support through the dock connector, but there are no commercially available compatible microphones. People have made their own to use with jailbreak VOIP apps. No idea how well it would work as an 'area mic' for picking up lectures, etc.
If you're gonna be recording lectures, you're better off buying an actual voice recorder. They have better quality in the end, which is what you'll need to be giving out your lectures =]