Audacity is a great free audio editing program.

From their website (http://audacity.sourceforge.net/about/)

Audacity is a free, easy-to-use and multilingual audio editor and recorder for Windows, Mac OS X, GNU/Linux and other operating systems. You can use Audacity to:

* Record live audio.
* Convert tapes and records into digital recordings or CDs.
* Edit Ogg Vorbis, MP3, WAV or AIFF sound files.
* Cut, copy, splice or mix sounds together.
* Change the speed or pitch of a recording.
* And more! See the complete list of features.

You can get Audacity here http://bit.ly/audacity1