Blogger now supports custom domain names for your blog, earlier you had to choose a sub-domain address on *.blogspot.com. Now, as Google says —”you can get a domain of your own. We'll continue to host all your content as before, but it will be displayed at your new address.”
Your Domain: The first thing you'll need to do is to choose a domain name, like mysite.com and register it. You can register domain names from any of a number of different registrars, and you can use .com, .org, .net or any other valid addresses. Remember: you only need to get the domain name; you don't have to pay extra for hosting service.