(for ssh from a windows machine, please see this help page).
SSH is quite easy from an OS X machine. Open up the terminal application. This can be found in Applications-->Utilities-->Terminal. Double-click on the terminal to open up a terminal window. At the prompt, type in:
ssh -Y username@machinename.shadlen.org
where username is your shadlen login name, machinename is the hostname of the machine you are logging into, and -Y gives you graphics.
If your username is maria, and you want to log into nina then your terminal will look like this:
That is all there is to it. You will then be prompted for your password. The -Y is for using X windows, so if you are not planning on using X windows, you can exclude the Y. More information on using X windows on a mac is in the HowTos.MacX. If you are using the same login name on the OS X machine as your linux login (for instance, if you logged into one of the OS X machines in the lab), then you don't even have to include the username@ part, just ssh coltrane.shadlen.org
SSH from OS 9 involves getting some software, but is extremely simple to get going. The application is MacSSH.
Once you have the software installed, just make sure to click the Secure Shell V2 checkbox when you open a connection. You can use any of the machines listed on the intro page, just use shadlen.org at the end.
Note that the ssh client provided by the UW uses Kerberos for its authenticating, and since we don't, you will be unable to use this software to connect to the shadlen machines. Of course, you can use MacSSH to connect to the UW. If you used Nifty telnet in the past, this will no longer work, since it uses sshv1, and we have upgraded to sshv2.