WordPress.org

• Upload WP-Universe to your blog's wp-content/plugins directory
  • Activate the plugin
  • Goto category managment and for each category you want to be served as sub-universes, put URL of sub-universe to categories description field.
  • Enable/Redirect subdomain/domain to your Wordpress installation.

To better understand step 3;

• Let's say we got our blog at http://www.myblog.com and have a category named Wordpress. We want it to be served as http://wordpress.myblog.com
• Goto category managment [Managment/Category Menu under Wordpress Adminstration]
• Find Wordpress category and click it to edit.
• Write http://wordpress.myblog.com to description field of the category and click "Edit Category"
• Add a subdomain using your hosting control panel/dns controller to your default IP.

That's it!