After upgrading to Tiger, I had to reconfigure my system to enable X11 forwarding (so I could use DBDesigner over the network). To enable X11 Forwarding, open /etc/ssh_config (you need root privs). Change “Forward X11 no” to “Forward X11 yes”, and remove the pound sign from the beginning of the line.

One other Unix hint:
To refer to the last argument from your last command, type !$.
To refer to all args from the last command, type !*.
To refer to the nth arg from the last command, type !:n, where n is the arg number.
I pulled these refs from here.

**UPDATE - srhaber 9/7 **
I discovered it is not necessary to change the /etc/ssh_config file at all (which is great if you lack sudo privs). If running Panther, use the -X argument when establishing the ssh connection:
> ssh -X hostname

In Tiger, use the -Y arg:
> ssh -Y hostname

The -X argument enables X11 Forwarding, and is available to ssh in both Panther and Tiger. The -Y argument enables “Trusted X11 Forwarding” and is only to available to ssh in Tiger.