Audacity is a free full featured sound and audio editor and recorder.

Audacity has many professional features with the ability to aquire sound from multiple sources such as a microphone or minidisc with up to 16 sound channels allowing you to mix music or other sound.

Audacity can also import and export various sound formats such as WAV, Ogg Vorbis and MP3.

Other features include sound editing like mixing music or other audio tracks, copy and pasting sound blocks, remove unwanted noise from background (eg static, hissing and humming noises) and applying special effects (echo, phaser, wahwah and reverse)

This is a very professional and free audio package.