How to remove your Blogspot account
Can you delete your account? Yes and no. Not for individual Blogger/Blogspot accounts, because these sites belong to Google. See http://www.google.com/support/blogger/bin/answer.py?hl=en&answer=41932 where you can read how to (at least) erase your blog entries. However, you can terminate your account by removing your Google account. See the Google entry on this site. Not a very neat solution.
Helpful Trick: Removing online data
Helpful Trick: Remove third-party logins
If you signed up for Blogspot using a third-party login such as Facebook or Twitter, you probably want to revoke all access from Blogspot. Click here to find out how.