some simple things to improve security of the ssh server...
change the password for the user pi. from a terminal:
passwdenter the current password (default is raspberry). then enter a new one. if you plan on exposing the ssh server to the outside world i suggest you make it something strong as people regularly scan the open internet looking for ssh servers to run brute-force password attacks against.
i would strongly suggest at this point that you read the following HOWTO on securing ssh and at least implement steps 1 and 2. step 1 is not strictly necessary as no root password is set by default so root login would not be possible, but it's good practice to disable root logins on ssh anyway.
sudo apt-get install tightvncserver
vncserver :1 -geometry 1680x1050 -depth 16 -pixelformat rgb565
sudo -u pi vncserver :1 -geometry 935x950 -depth 16 -pixelformat rgb565