3 - Phonon (either from Qt 4.4, or from KDE4 with some 'pursuasion' - KDE's version is not officially supporeted by Jerboa)
4 - A phonon backend (on any Qt-supported platform, Qt includes one. kdelibs 4
5 also includes a xine-lib backend if you're on Linux)
6 - Appropriate plugins for the backend you're using (eg if using gstreamer, you
7 probably want gst-plugins-base, gst-plugins-good, gst-fluendo-mp3).