Audacity

uts for your audio creations. It can capture up to 16 different channels at once. Audacity X supports WAV, AIFF, AU and OGG Vorbis. If you want to work with mp3 files you'll need to install LAME encoder. Cut, copy, paste, add echoes, fade, inversion,... do whatever you want and create your own audio masterpiece. If you think these features are not enough for you, install some plugins and power it up.