Gmail currently only accepts secure incoming connections if you are using Google as your SMTP server.  Since FogBugz doesn't do secure SMTP communication out of the box, we just need to use stunnel to set up a secure tunnel first.  It took me less than five minutes to set this up following the instructions on the Mailtraq knowledge base.

These instructions are for windows only, but if you are an administrator on your Linux/mac machine, you should be able to get this running also.

1. Enable POP3 access to your gmail account.  You need to do this even if you're only going to use it for SMTP.  See Google's help for more info.
2. Download stunnel.  Grab the latest .exe installer and run it on your FogBugz server.  This will place stunnel.exe into c:\program files\stunnel
3. Configure stunnel to use Gmail.  Open up the stunnel.conf file in c:\program files\stunnel and replace the entire contents of the file with:
   

   client = yes
   output = stunnel-log.txt
   debug = 0
   taskbar = yes

   [SMTP Gmail ]
   accept = 127.0.0.1:1099
   connect = smtp.gmail.com:465

   [POP3 Gmail ]
   accept = 127.0.0.1:108
   connect = pop.gmail.com:995

4. Arrange for stunnel to start as a service.  Go to Start->Run and type 'cmd' to bring up a cmd window.  Now type "C:\program files\stunnel\stunnel.exe" -install  This will create an entry in the Services control panel, which you can now open, right click on and choose "Start" to get stunnel running as a service.

5. Go into FogBugz and set your SMTP server to be localhost, the SMTP port to be 1099, and the smtp username and password to your Gmail username and password.

6. Using Gmail for Domains?  The only difference is that you want your username for SMTP to be your full username including your domain.