Audacity

Product Overview
Audacity is a free, open source software for multi-track recording and editing. With Audacity, creatives of any skill level can record live audio through a microphone or mixer, digitize recordings from other media, and capture streaming audio (Windows) for use in Podcasts, video clips and any other use.

• Record from microphone, line input, USB/Firewire devices and others.
• Import sound files, edit them, and combine them with other files or new recordings.
• Export your recordings in many different file formats, including multiple files at once.
• Licensed under the GNU General Public License (GPL) for Windows, Mac and GNU/Linux.
• For advanced users, nightly builds are available for testing purposes (alpha builds from latest development code).