It's cool for lots of stuff - voice recording, editing a long recording into a bunch of sections and sampling a ring tone for example. You can also use it to record direct from your computer - so, say, you had a radio programme that you couldn't download...
You can download the latest version of this little beast from the Audacity site. It's not a big download and it's pretty stable and simple enough to use - stick a comment on this if you want to check something. You might need to get your hands on a mic if you want to dub your voice onto some sound, but they're pretty cheap to get hold of.
Look, the basic buttons look just like an old fashioned tape recorder. Even oldsters like me can work our way around that!
I'd start by getting an mp3 track (or whatever - it'll deal with lots of formats) into the software and start to play around with the various editing tools. Highlight some of the sound and see what you can do. The Effects menu is quite funky, but also try cutting the file around.
Then see if you can add two tracks at once. You might even be able to mix them into each other if you play around enough - the Audacity site has a pretty sound (ha ha...) set of help files and tutorials that should help you along with anything you get hideously stuck on.
The whole thing is easy enough to use. Just highlight want you want to edit and edit away.
The one issue you might have is being able to record your voice easily. Try Edit > Preferences and change the recording device to whatever's on the bottom. That might work.
I don't remember if you need to then change it back to something else to record sound from your soundcard. Try it and see!
Free, fuggly and funky. What more could you want?