Audacity is free, open source software for recording and editing sounds.
With Audacity one can record live audio, convert tapes and records into
digital recordings, edit Ogg, MP3, and WAV sound files, and much more.

Audacity requires either wxPython or wxGTK.

Support for optional dependencies can be enabled passing the script
optional parameters, such as:
FFMPEG=yes     (requires ffmpeg)
SOUNDTOUCH=yes (requires soundtouch)
TWOLAME=yes    (requires twolame)