Assuming you are using 6.10 onwards (6.06 didn't have it) if you go
into synaptic look down the list of packages you'll come across
meta-packages > Xubuntu-desktop & Kubuntu-desktop are there. Sorry i
can't check as my linux machine is in the middle of a rebuild - i'm at
the stage where i'm putting all data on a external drive and
rebuilding both machines now that i've taken the step to do make linux
my main machine... winblows in reserve just in case.