"Synaptic" > Menu line > Settings > Repositories.
A dialog window will open : please mark e.g.
... then add kde4
to the line "Section(s)".
... next : click "Reload" to have all KDE4 + amarok2
included in Synaptic.
And amarok2 ( amarok-2.1.80-1pclos2009, 05-Sep-2009 23:23 10M )
can be installed with a click ... you will also be able to see,
which dependencies are installed together with amarok2.
The packages are here, if you want to have a look :