How do I get Audacity or Virtualdub to do this?

I load a video, and I want to take the audio and make into an MP3. Audacity does it, but its all crackly. How do I fix the horrible feedback with Audicity? And, how do I cut Audio using VirtualDub?How do I get Audacity or Virtualdub to do this?
Glad you figured it out.

I was going to say the issue with Audacity may be related to the LAME encoder settings. Feedback would make me think your audio input is also taking the mic in.

Or you could have noise from the video channel if you're loading that directly. I've never tried loading a video file directly into Audacity.