WordPress plugin Repository has a new plugin that lets you make website migration from one domain to another very easy. So next time you need migrating your WordPress site to a new domain, all you will be needing to do install and activate the plugin Automatic Domain Changer. After activation visit your admin area Dashboard -> Tools -> Change Domain (remember to keep a backup for safety).
Now type your new domain name (where you are migrating your website) in ‘Change domain to‘ text box and click the button Change domain. This updates your database tables with new domain name and a notice appears at the top of the admin screen with a link to the domain changing tool.