To add your blog in Technorati you will have to sign up first at Technorati, update your profile, and at the end of page you will get an option to claim your blog.
Enter the details to claim your blog and you will be provided a short code which should be present in a post on your blog by email and on the profile.
Login in your admin area of blog, add new post or edit any existing post and add the short code provided by Technorati in the body of the post like in this post
My Technorati short code is 5KE4HZTA6P8Y
Once you have added the short code in the post , go to Technorati and click on "verify claim token".
Once your blog is claimed you can delete the post or remove short code from the post.