Wordpress 3.0 saw the addition of a wonderful new feature - multisites. What are multisites? They allow you run multiple blogs from just one WordPress installation. Each blog can have different users, different themes and different plugins.
This is possible because the old WPMU (WordPress Multi-User) project was merged into the main WordPress system. This is the same codebase that allows WordPress to run millions of sites, so you can be sure it works well.
In order to set this up, you will need access to your files so that you can edit them. This tutorial will show you how. When you've finished, click here to read Part 2 of this tutorial: Managing WordPress Multisites
In your files, browse to wp-config.php and open that file.
Scroll right to the bottom until you find this line: /* That's all, stop editing! Happy blogging. */
Just ABOVE that line, enter this line: define('WP_ALLOW_MULTISITE', true);
Save that file and login to your WordPress admin panel. Hopefully you'll be able to click on "Tools" and see a "Network" tab has been activated:
Configure the Multisite Network
If you click on Tools then Network you'll see a screen like the one above. You can name your multisite network, set and admin e-mail address and then click "Install"..
You'll see a screen like the one below. It's going to ask you to complete three more steps to set up your network:
Step 1: blogs.dir folder
In your main /wp-content/ directory, simply create a new folder called /blogs.dir/. This is where all the files uploaded by your network users will be stored.
Step 2: Edit wp-config.php again
WordPress is going to ask you to go back to the same place in your wp-config.php as before and cut-and-paste the code it gives you.
Step 3: Create and Edit an .htaccess File
Finally, you'll need to create a file called .htaccess. This should be sitting right alongside the /blogs.dir/ folder you created earlier. Open the file and paste the code it gave you earlier:
Multisite Setup Success!
Hopefully now you've gone through this process, you'll be able to login to your WordPress admin area and see two new links in your admin panel: Super Admin and My Sites.
Woohoo! You've successfully set up WordPress multisites. Now, click here to read Part 2 of this tutorial: Managing WordPress Multisites.