I am pleased to announce that despite our decision not to switch shared hosting customers over to PHP5 on account of compatibility risks, we have now made it possible for customers that wish to begin using PHP 5 features to do so without interfering with existing customers using the PHP 4 installation.
PHP 5.1.2 is now accessible via the FastCGI Apache module. I was able to easily drop this module into the existing configuration and to set up the php-cgi binary installed by H-Sphere for PHP 5 so that it could be activated through two simple lines in .htaccess. Instructions on how to do this are available here.
Next on my todo list is tackling mono support with mod_mono. This module will allow the support ASP.NET features on Linux web services, eliminating some customers' need to use Windows hosting. I am still working on learning how to drop in MySQL as a replacement to MSSQL, but the basic ASP.NET functionality is working well, so look for that feature to become available over the next month or two.