Did you know that you can run multiple site off the same installation of WordPress? Yes, WordPress 3.0 featured the merger of WordPress-mu into the source. And now that you already have it setup, turning on the multi-site features in only a few click away. And this will allow you to run multiple websites including the ones on separate domains (TLDs), sub-domains or sub-directory based structure.
Open the wp-config.php file using your ftp client/file editor and add the following line right before where it says — /* That’s all, stop editing! Happy blogging. */
Once you do this, you’ll have access to the multi-site feature under the Tools menu called “Network”. Now you are ready to setup wordpress multi-site network. Just fill up the form and follow the on screen instructions. Additionally you may want to configure wordpress multi-site for separate domains and if you own it, use Thesis with WordPress Multi-site.