I've just downloaded WaveShop from the link above. It was a quick hassle free download. I found an mp3 file and was able to edit it without any bother.

When I edit the minimum I want to do is chop the unwanted bits from the beginning and end, fade in and out and set the overall level or normalise the track.

I can do all of this easily on this program. It saved the mp3 and also converted it to wav and was prepared to recognise a wide range of recording formats. If this is the sort of thing you want to do then this program can do it.