I wanted to play around with sending video to YouTube.  So I put together a few minutes on how I do noise reduction using soundtrack pro for podcast tracks.  I use a combination of soundsoap (http://www.bias-inc.com/products/soundsoap2/) and the built in noise reduction in Soundtrack Pro.    Alternatively instead of soundsoap another even better and of course more expensive noise reduction plugin is MR Noise (http://wavearts.com/products/plugins/mr-noise/)