There is more information on this at
https://wiki.ubuntu.com/Xubuntu .
You can do a server install and the install xfce and the programs you need or you can
Code:
~$ sudo apt-get update
~$ sudo apt-get install xfce4
which is what I did. I recommend the server install, but if you don't want to reinstall your whole operating system, you can try the latter.
another option that has already been mentioned is
Code:
~$ sudo apt-get update
~$ sudo apt-get install xubuntu-desktop