First, log in to your account at the appropriate host (course1.hmdc.harvard.edu) with SecureCRT (or some other encrypted telnet). Then, to findout which VNC session belongs to whom, type vncfinger at the command prompt in the telnet window and you will see the output:
Username VNC Session gov2001 2 mathpre 3
Alternatively, if you type: vncfinger username you will see:
Username VNC Session gov2001 2