Terry taught how to combine multiple WordPress sites using the built in Export and Import features of WordPress. He also showed how to add 3 lines of code to the sites that the content was exported from so that all links would still reach the content but on the domain that it was Imported in to.
The code to add to the top of the .htaccess file is:
RewriteRule ^(.*)$ http://www.newsite.com/$1 [R=301,L]