Just try to install SCPlugin, a Finder contextual menu for Subversion (svn). Works just as well as TortoiseSVN does on Windows, so I am a happy camper.
In case you try to build and install it yourself, the installation file misses one minor point. Once you have installed it, and restarted the Finder, you have to go to its preference pane and turn it on! I would have expected it to be on by default.
Jolly useful though, for those commandline disadvantaged.