Long time ago when I used to write my computer articles I'd already introduced Audacity: Free Audio Editor and Recorder.
A few days ago I was digitizing my tapes and I figured how to use the cool "Noise Removal" feature of the program: Once you record a song in Audacity select a part of the track with no voices other than the white noise (probably the very beginning and the end), then go to Effects, select noise removal and click on "Get Noise Profile".
Then select the whole track, go back there, click on "remove noise" and bingo!
