Subversion 1.1 (and later) has the ability to put a symlink under version control by using the svn add command.
The Subversion repository has no internal concept of a symlink. It stores a "versioned symlink" as an ordinary file with an svn:specialproperty attached. The svn client (on unix) sees the property and translates the file into a symlink in the working copy. Win32 has no symlinks, so a win32 client won't do any such translation, and the object appears as a normal file.