All you need in your stunnel.conf file is this:
client = yes [smb] accept=10.1.1.2:139 connect=samba.cs.umd.edu:1445
Note: Installing and starting a service means that the stunnel connection will be available whenever you restart your system. If you want to run it manually, skip the service install and start steps, and just run stunnel manually ( Start -> All Programs -> stunnel -> Run stunnel )