Best practices when moving your site

Your aim is to make the transition invisible and seamless to the user, and to make sure that Google knows that your new pages should get the same quality signals as the pages on your own site. When you're moving your site, pesky 404 (File Not Found) errors can harm the user experience and negatively impact your site's performance in Google search results.

Link:
http://googlewebmastercentral.blogspot.com/...