Adjusting music - slower/faster

I us a freeware program called Audacity to adjust the temp/pitch/length, whatever, of otherwise suitable tunes for demo music or so it can be played at a social.
What other programs do people use, and are they easy (I'm far from being a computer nerd (except for Photoshop Elements).

And while we're at it, which songs do you adjust for what dance and by how much (so we can do the same)?
Metallica do a great viennese, (Nothing Else Matters), can't remember the adjustments I applied, but quite a bit of speeding up as well as shortening it (if the thread is useful I will find out). It's got great power to it (no surprise being metallica).

Graham