Conditional Execution of PHP in Apache

[WaveyDavey]

Not sure how to describe this.
We have a school site which is heavily developed in php and works fantastic. Php tags are parsed in extensions php AND html.
We want to add student areas (like www.ourschool.org/~bloggsf) where students can post up web pages.
However, for security reasons, we would like apache NOT to parse <?php code in their areas. In fact, we dont want them doing any form of CGI really, cos the little blighters will wreck *something*, guaranteed!
This is on Apache2, on a Fedora core 4 box, php5.1.2.

Many thanks
David