coopster - 3:26 pm on Dec 27, 2008 (gmt 0)

Depending on which version of PHP you are running, you may be able to use Recursive patterns [php.net]. They are a bit more advanced but pretty powerful once you get a grip on them. The PHP manual page I linked to there has some information but the perlre [perldoc.perl.org] manual page has much more information.