As mentioned above, Audacity is THE tool to use for this. It is multi platform (runs on Linux, but has also been ported to windoze. There is even a portableapps version of it which means it doesn't need to be installed on every PC, you can take it along on a USB stick and run it directly from there. I always prefer portableapps tools over other standard software:
http://audacity.sourceforg
P.s. It is open source so completely free of charge.