This functionality is very different from the actual command line svn export url [-rRevision]
If you are thinking about checkout out a single file at a particular version, keep looking because this export can not perform that functionality.
(PECL svn >= 0.3.0)
svn_export — Export the contents of a SVN directory
Export the contents of either a working copy or repository into a 'clean' directory.
The path to the current repository.
The path to the new repository.
If TRUE, it will export uncommitted files from the working copy.
Returns TRUE on success or FALSE on failure.
Example #1 svn_export() example
$working_dir = '../';
$new_working_dir = '/home/user/devel/foo/trunk';