Google’s Webmaster Central blog wrote some best practices for moving your site to a new domain. I am happy with Google’s write up and it is a great first step, but I am a strong advocate of a Google Certified Domain Change process within Webmaster Tools.
In any event, here is a summary of what Google recommends:
- Test moving part of your site to the new domain first.
- Use 301 redirects to notify Google of the change.
- Redirect your pages to the most relevant new page, when possible.
- If you are also rebranding your site, consider first moving the original site and then doing a redesign.
- Make sure your internal links are pointing to the new domain.
- Try to encourage external links to change to the new domain.
- Hold on to the old domain for 180 days
- Register and verify the new site with Webmaster Tools and then submit a sitemap.
- Review crawl errors within Webmaster Tools on both the new and old domain.
I have some additional resources at the Search Engine Roundtable on moving domains.