Subversion supports symbolic link, as stated in http://subversion.tigris.org/. Here is the quote:
Unix users can place symbolic links under version control. The links are recreated in Unix working copies, but not in win32 working copies.
it's simple to test this. In a directory where you have svn code checked out, do
% ln -s file file_link
% svn add file_link
% svn ci
Then from somewhere else update or checkout this portion of svn, and you will see the soft link exist.