Extract audio from avi/mpg?

[Udon]

How can I extract audio from a video file and convert it to mp3? Can virtual dub do that?

[JKTrix]

Unfortunately I can't provide a link to any further detailed information, but WinAmp has a plugin that records audio from a video file as a WAV, then you can probably use Audacity to compress it into an MP3.

[Samuraid]

Virtual dub can save the audio track from an AVI file. (Look in the menus, the option should be there).

You can then use whatever program you like to convert to MP3.
CDex (http://cdexos.sourceforge.net/index.html) has a MP3 encoding in it so you could use it if you don't have anything else.

[o_O]

Further to what Samuraid said, Virtual Dub (or Virtual Dub Mod) is one of the best free video hacking tools you will find.

No matter what you want to do, there always seems to be a way to do it in Virtual Dub. :p
I highly recommend it.