Boxee
From TGB WIKI
Download and install this streaming TV, movie, music and photo aggregator and launch it from Media Center with this add-on! Also plays local media! Boxee works with XP, Vista and Win7, but the launcher is only good for VMC/7MC. Could also be added using MC Menu Mender/MC Studio.
Links
http://www.missingremote.com/index.php?option=com_content&task=view&id=3285&Itemid=1