For a system wide installation use (PREFIX: /usr):
(this should match where SC is installed, so this version if installed from a package)

sudo sh install_linux_system.sh /usr

or (PREFIX: /usr/local) (if SC installed from source)

sudo sh install_linux_system.sh /usr/local

For a local installation (in the home directory) use (PREFIX: ~/share/bin):

sh install_linux_local.sh

Check whether you have sun java installed
On Debian/Ubuntu the package is called
sun-java6-jre

sudo apt-get sun-java6-jre

Add these lines to your .sclang.sc

GUI.swing;
SwingOSC.java = "/usr/lib/jvm/java-6-sun/jre/bin/java";
SwingOSC.program = ("PREFIX/bin/SwingOSC.jar").standardizePath;
SwingOSC.default.boot;

The actual java executable location may vary with different Linux systems.