Audacity

Audacity is a free, cross-platform audio editor written in C and C++ using the wxWidgets toolkit. It was started in 1999.

Advantages:

• Open source (Released under the GPL License)
• Cross-platform - (Linux, Mac, and Windows)
• Multiple tracks
• Capable of Ogg, FLAC and MP3 encoding/decoding, the latter with use of an external lame-encoder.

Disadvantages:

• MP3 encoding is not included (the algorithm is patented), but you can still download it for free.

External links

• Audacity sourceforge page
• Audacity screenshots
• Audacity Wiki
• Audacity user forum