WordPress MU

We currently have a single WP blog on our site that's up and running just fine. It doesn't have it's own domain name - it's http://www.oursite.com/blog.

We now have the need for multiple blogs so I'd like to 'upgrade' to MU, but I don't want to 'break' the existing blog. Is this possible? Can anyone point me to a how-to?

Thanks!

Forgot to mention - the server is Windows / IIS.

The best bet is probably to use the built-in Import/Export tools in WordPress.

Export your current blog (Tools menu -> Export). This will give you an XML file. Back up your wp-content folder.

Delete all the WordPress files, including database tables.

Download and install WPMU.

Once you are logged in as an admin, go to Tools -> Import. Import the XML file you created above. This will set up your "current" blog as the root blog in WPMU.

That should do it. Make sure to back up everything before you do this, so that you can restore if something goes wrong.

Thanks for the response! Will that method maintain our plugins and theme?

Yes, as long as you back up the wp-content folder. Once you've installed WPMU, you'll have to put everything from your old wp-content folder into the new one that is created. You'll also have to activate the plugins and themes again.