First, you need to make sure you have an svn client installed on your remote machine. For a mac, the easiest thing is to download the client from http://www.codingmonkeys.de/mbo/.
This will allow you to use the command line (terminal) to interact with Subversion, but there are also some nice GUIs available. I particularly like svnX, which can be found here. You will undoubtedly have difficulties authenticating using the GUI. This web site has steps spelled out to overcome this.
to initially checkout files in your personal repository (using miles as an example, but can use any of the cluster machines):
svn checkout svn+ssh://miles.shadlen.org/home/svn/test
to initially checkout files in the lab repository:
svn checkout svn+ssh://miles.shadlen.org/lab/subversion
Once you have checked them out initially, subversion will know where to go. So, when you want to commit your changes, you can just type:
svn commit -m "fixed a few typos"
and as long as you are in your svn directory, you will be using ssh automatically to contact the server. You will still have to enter your password, of course.