Note you first must determine whether or not the site is a free hosted WordPress>COM blog or not. Many people assume WordPress.ORG installs are hosted by WordPress.COM when they aren’t.
To determine whether or not the blog is hosted at WordPress.com.
If you see a link that reads “Blog at WordPress.com” in the footer of the blog (linked to http://wordpress.com), this normally means that it is hosted here (although external blogs may place this in the footer, if they choose to). Also, if you are logged into WordPress.com, you will see your gray-colored admin bar at the top of your screen.