Audacity

Audacity is an Open Source, free, easy-to-use audio editor and recorder. You
can use Audacity to: Record live audio, Convert tapes and records into
digital recordings or CDs, Edit Ogg Vorbis, MP3, and WAV sound files. Cut,
copy, splice, and mix sounds together, Change the speed or pitch of a
recording, Remove static, hiss, hum, or other constant background noises. (in
Home and Hobby)