Audacity is a free, easy-to-use and multilingual audio editor and recorder. Basic features, as listed on their website, include:

Record live audio.

Record computer playback on any Windows Vista or later machine.

Convert tapes and records into digital recordings or CDs.

Edit WAV, AIFF, FLAC, MP2, MP3 or Ogg Vorbis sound files.

Cut, copy, splice or mix sounds together.

Change the speed or pitch of a recording.