Skype started a new service offering the online status of a user in his skype button.
You can create your own HTML code and paste that on your site http://www.skype.com/share/buttons/wizard.html
Previously, you had to use tools like http://www.onlinestatus.org/usage.php to show the current status of your instant messaging client.
Blogsphere will use this feature in version 2.5.4