You can just download the binaries for the client (http://subversion.tigris.org/). If you want menu and icon support when browsing files, there's SCPlugin for the Mac's Finder or TortoiseSVN for Windows. If you want a GUI, note that the Mac's native Xcode environment has Subversion support built-in.
There's a beautiful app, Versions, http://www.versionsapp.com/, but it's around US$50. That's the one we use.
There's SvnX, http://www.lachoseinteractive.net/en/community/subversion, which is free but ultimately not very good (in our experience).
There's ZigVersion, http://zigversion.com/; no opinion.
But, really, a 5-second effort with Google would turn up all of this and more:
http://en.wikipedia.org/wiki/Comparison_of_Subversion_client... .