Step 1: In this article, it mentioned a tool which can help you set it up quickly. After enter your own domain, once click confirm, DNS will be set it up automatically for Blogger.
http://nz.godaddy.com/blog/bloggerdnssetup.aspx?isc=bb2470
Step 2: Last step, Blogger will give you two CNAMEs to enter on GoDaddy, one is a common one (Name:www, Destination: ghs.google.com), another one is for your blog only. Previous tool will set up the common one on Godaddy, all you need to do just the second one as following. Then submit zone file on the top right.
Step 3: Don't forget to set up your custom domain on Blogger. Setting=>Basic=>Publishing=>Edit
Done! After an hour or so, enter your custom domain, it will redirect to your Blogger's blog.
happy blogging...
