I recently migrated mspwordpress.com to mspwp.com. Using a WordPress plugin was an option, but it didn’t seem ideal, since I wanted to maintain all SEO stuff for all pages. The solution was to use .htaccess as follows:
Options +FollowSymLinks RewriteEngine On RewriteBase / RewriteRule ^(.*)$ http://www.mspwp.com/$1 [R=301]
Pretty neat, eh?