When you switch domains for a WordPress installation, you should think of not only the how to move the site, but how to keep your content reachable by search engine hits or referrals. 301 Redirect is what is expected of you, and the easy way to do it, even if both domains are still hitting the same directory on the server is by adding the following rewrite condition and rule in .htaccess (works for sites hosted on Apache only):

RewriteEngine on RewriteRule (.*) http://www.newdomain.com/$1 [R=301,L]

1 2	RewriteEngine on RewriteRule (.*) http://www.newdomain.com/$1 [R=301,L]