Matt Wiebe

Many older WP sites used categories and/or pages to organize what were essentially subsites without proper access control and other site-specific goodies like themes, widgets, and plugins.
This plugin lets you move that content to another site on your WordPress network with a single click, with seamless redirects.
This is beta software. Back stuff up first. (I shouldn’t have to tell you that, right?)

Move to Subsite

Move posts in a category and/or a page hierarchy to a new subsite, with seamless redirects.

chrisnowak

We do a lot of WordPress installs for clients when we set up new websites for them. One hassle we always go through is setting up the development site as a sub-domain or as a complete other domain, and then having to move it to the new domain. Since WordPress uses absolute URLs in posts, links, etc., editing by hand is definitely not an option. We also couldn’t find a really good solution, so I wrote a plugin that will go through all of your posts, pages, options and guids and update your old domain to your new domain!

Change WP URL

Use this only if you're trying to move your WordPress install to another domain.

Move to Subsite vs Change WP URL