How to use custom domain name for bloggers blog

The two ways you can publish your blog on Blogger is either you host it on Blogspot (example.blogspot.com) or host it on your own custom domain name (www.example.com or foo.example.com). You can change where your blog is published at any time, and it won't cause you to lose any content on your site.

 First, purchase a custom domain name from any of the link given below
Before you move your blog to a custom domain, you need to have already purchased a custom domain name from another provider.
There are many companies you can buy domain names from, such as:

• 1and1
• Yahoo! Small Business
• No-IP
• EasyDNS
• GoDaddy.com
• ix web hosting

Now set up your domain with your existing bloggers blog

1. Go to your blog and click on Basics under the Settings tab. In the "Publishing" section, click the link to add a custom domain.  
2. Type the url of the domain you've purchased, keeping in mind that it must begin with www in order to work.
3. Click Save.
4. You should see an error, and two CNAMEs listed below. Each CNAME is composed of two parts - Name, Label or Host and Destination, Target or Points to. The first CNAME is the same for everyone, Name being "www" and Destination "ghs.google.com." The second CNAME is particular to your blog and your Google Account, and is therefore different for each person.
5. Go to your domain registrar's website and locate the DNS (Domain Name System) settings in the control panel.
6. it's time to enter the CNAMEs. Where it says Name, Label or Host simply enter "www" and list ghs.google.com as the Destination, Target or Points to.
7. enter the second CNAME in the same way.
8. You can also enter A-records, which links your naked domain (example.com) to an actual site (www.example.com). If you skip this step, visitors who leave off the "www" will see an error page.
9. After completing Step 8, enter your domain name in the format example.com, and list the I.P. addresses shown below in the "A" section. You'll need to create four separate A-records which point to four different Google IPs. 216.239.32.21
   216.239.34.21
   216.239.36.21
   216.239.38.21
   
10. Wait about an hour for your DNS settings to activate. If you attempt the final step before your settings are activated, we'll let you know with a warning message.
11. After your settings have been activated, you need to make sure Blogger knows about your custom domain so that Google can direct readers to your blog. Just head back to Blogger and update the information on your Settings | Basic tab. Find the area for "Publishing," and click the link to add a custom domain.
          That’s it! Your blogspot.com address will soon redirect to your new custom domain -- be patient, as it might take up to 24 hours for the redirect to start working, good luck!