Amazon EC2上用于Apache的PHP模块

Using the basic Amazon 64 Bit AMI

and I do

sudo yum install php
sudo yum install httpd

However apache is not handling php files. When I visit one it just prints the source code to the browser. There is no php module in httpd.conf. How do I fix this? i.e. is there a different package to install or how do i modify httpd.conf to make it work.

Thanks!