Alar is correct about DH having removed the option to run PHP as an apache module from the control panel, but there is one other thing you could try. From an older KB article:
[quote]How do I switch my PHP between running as a CGI and an Apache module?
Of course you’ve already read all about the differences in PHP-CGI and PHP as an Apache module, right? And you know that the default set up is as PHP-CGI, which is heavily preferred, right?
If you still want to change your PHP setup, here’s how! Add the following to your .htaccess file:
AddHandler application/x-httpd-php .php
Note that this configuration is considered ‘unsupported’ by DreamHost and it may not always work in the future. [/quote]
I have no idea whether this will still work, but it might be worth a try?