If you need to find a Subversion client for Windows or just want to check out what else you could use, take a look at this comparison of client applications on Wikipedia.
The most used Subversion client is the command-line interface. This is now a separate download available from Apple's Developer website or from the Download section in Xcode's Preferences. Once installed, type svn --help in a Terminal window to get an overview of available commands. The SVN Book offers a immense wealth of knowledge about the command-line interface and Subversion in general.