You can use the old air poppers to roast coffee but i have never tried it my self.

If your thinking about it start here http://www.sweetmarias.com/index.php
i got 2 of my home rosters form them and my last coffee pot "Technivorm Moccamaster".

I order my green coffee from http://www.thecaptainscoffee.com/

Be warned if you start home roasting you'll never go back to drinking the coffee at work or star bucks, it will all taste like crap