There's a Python script that is written to update the Skype mood message when amaroK changes tracks. For reference, amaroK is a media player.
It is meant to be ran inside of amaroK, but I'm sure it would be fun and easy to modify it to suit your purpose.
http://www.kde-apps.org/content/show...?content=55794
Download and unzip the file, make sure you have all dependencies, then run it on the command line, by doing python <scriptname> (don't use the angular brackets). If all goes well, Skype will pop up a dialog asking you if you want this program to allow interfacing.
After have ascertained that the script works (doesn't throw errors, and causes Skype to ask confirmation), you can then go about changing the script.