Recently WordPress 3.1 was released and there was a new feature known as Admin bar. If you login to your self hosted WordPress blog then you will notice a bar at the top which have many useful shortcuts of most important areas at the backend. Below is a screenshot of admin bar.
How to remove or disable admin bar on my WordPress blog
Step 1 : Go to Dashboard==>Users==>Your Profile.
Step 2 : Then uncheck the box when viewing site which is in the front of Show Admin Bar and then click on update profile.
Now admin bar has been disabled. I personally like the admin bar, if you change the mind and want to get the admin bar back then you can get back by the same procedure just check the box in step 2 ( instead of uncheck ) and click on update profile.