As a part of the Bricolage project, there's a note about the PHP5 templating support that he's implimented - in Perl.

So how did we add PHP 5 templating to a mod_perl application? Easy: we hired George Schlossnagle of Omni TI to write PHP::Interpreter, an embedded PHP 5 interpreter. Now anyone can natively execute PHP 5 code from a Perl application. Not only that, but the PHP 5 code can reach back into the Perl interpreter to use Perl modules and objects!

From the looks of things, it's quite a handy little module for PHP coders to use, and makes using Perl modules as simple as (*cringe*) using them via an eval. He gives a few code examples, both of just the module itself in use and of the module in use in the templating system...