If you change domains and want to let Google, search engines and old links know and redirect to your new domain heres is how to do it. It involves editing your .htaccess file in the root of your old domain and adding a 301 rewrite rule. The 301 rewrite rule means the url has been permanently moved.
Here is what to put in the
.htaccess file for your old domain, dont forget to change
http://www.thenewdomain.com to your actual new domain.
RewriteEngine on RewriteRule ^(.*)$ http://www.thenewdomain.com$1 [R=301,L]