Php Howto

Does Codefilter help ?
http://www.asymptomatic.net/wp%2Dhacks/

I would guess that you would have to link to another page on your site then.
Save the file you want as .phps, and put this line into your .htaccess page:
AddType application/x-httpd-php-source .phps
That will colour the php text.
HTH