musiCutter 0.7.1

This is by far one of the most useful music joining programs I have used. Most that I have seen are command line and/or needlessly complicated. This one has a simple UI, is easy, is intuitive, and best of all it is FAST. I highly recommend using this for things like audiobooks or if you want a full album mp3. Keep in mind that since it is so simple, it won't give options such as what bitrate to have for the output, so you just have to make sure your input files are at the rate that you want before you start.