One of my first projects at my new job entails taking three owned domains/separate sites and having them controlled via a single content management system.
I haven’t had any experience doing this since working with WordPress Mu at a former job way back when.
Since WordPress 3.0, this multi-site code is already part of the core and just needs some modifications to the WordPress config files to bring it alive. The article below is a great tutorial on setting that all up.