If you have a need for a digital camcorder, go that route. As mentioned, most (though not all - check first!) will perform a pass-through function that allows you to hook up an analog video source and record into iMovie.
If, however, you don't want a digital camcorder, there are many devices that will perform the function standalone, for about $200. I've been using the since-discontinued Dazzle Hollywood DV Bridge (or whatever the heck it's called). It works fine. I would assume that most of the ones on the market, including the Formac, do a reasonable job. I know that the Mac magazines (MacWorld, MacAddict, etc.) review this stuff from time to time. Can't remember the latest recommendations. I'm sure there are plenty of people here who can give advice.