In the ever-growing list of cool Media Center third-party software, I ran across mcePhone (thank Apple for the camel-case) that let’s you make Skype calls right from Media Center or a Media Center Extender. Since the Xbox 360 can be a Media Center Extender, MCE+Xbox+mcePhone = VOIP on your Xbox. How do I dial Bill Gates on this thing? 
That would be awesome! Is there a way to use Skype through my xbox360?
THIS DOESNT WORK YOU POORLY RESEARCHED EXCUSE FOR A ‘BLOGGER’!
RTFM http://www.scendix.com/mcephone/faq.php