Audacity is a free, open source audio editor and recorder that can be used to record, edit, and export audio files in MP3 format. It is available for Windows, Mac OS X, and Linux. To use Audacity, users download and install the software from the Audacity website. They can then record new audio by pressing the record button and export finished recordings in MP3 format through the export menu. Existing audio can also be edited and shared online through services like Podomatic.