All OSInet code and a growing fracon of Drupal code and other frameworks need PHP5, and this will become more important now that PHP4 has been obsoleted the the PHP Group (http://www.php.net). However, in spite of the GoPHP5 effort, many low-cost hosting providers still default to PHP4 to support the larger PHP4 preexisting code base.
However, most will also offer PHP5, depending on hosting plan configuration. This page list know tweaks to activate PHP5 on various hosting providers.
Submit your tricks here (need to register), or just send them by mail to support (at) osinet.fr to be included here
Add this to your .htaccess:
AddType x-mapp-php5 .php AddHandler x-mapp-php5 .php