Copyright (c) 2009 (email@example.com). All rights reserved.
Followed by whatever licence you wish to release it under.
For Perl code that is often just:
This module is free software; you can redistribute it and/or
modify it under the same terms as Perl itself. See perldoc perlartistic.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.