SSH (Secure SHell) is a remote access applicate that uses the SSL (Secure Socket Layer) protocol to encypts connections between two machines for security purposes.
All linux machines have an ssh client installed apptly named "ssh". To ssh to another machine simply type "ssh hostname" on the command line where hostname is the name of the remote host you're trying to connect to.
ssh clients are available for non unix platforms such as Windows and MacOS from here.
NOTE: The only way you'll be able to connect to our lab machines from off campus will be through the use of ssh.