I was playing around with the Rackspace® Cloud this weekend and came across two great tutorials for configuring CentOS 5.5 (one of the virtual OS images you can use) to be used as a standard web server.
The first tutorial I found covers setting up apache, installing MySQL and getting PHP installed along with the always useful PHPMyAdmin installation. It also had the useful line of code to allow port 80 use as this is blocked by default.
The second tutorial I came across was a simple guide to installing PHP 5.3 on the server (If you followed the first tutorial this also covers uninstalling the existing PHP version).
Overall the process of getting the Cloud server up and running was really smooth and I had a fully operational web server in the space of about an hour. It was also worth backing up the server image to the Cloud files to save time in the future setting up servers that need the same base config.