Bitnami provides complete free packages for OSS products like Joomla! and MediaWiki including everything you need to deploy such products on the server, typically Apache, MySQL and PHP and whatever else is required. Bitnami packages include all such necessary components, as well as the OSS product itself, and are designed to drastically ease OSS Web deployment.
The organization has just announced Bitnami Modules, which enables users to install several applications on a single stack. So if you are already running, say, Drupal on a Bitnami stack, and you also want to deploy WordPress, you can now elect to download the WordPress 'Module' from Bitnami and run that off the same stack.
Stacks currently on offer as Bitnami packages also include eZ Publish, Liferay, phpBB, DokuWiki and more.