I posted a link to the Lifehacker guide on how to do this earlier: http://lifehacker.com/5634515/how-to-synchronize-your-xbmc-media-center-across-every-room-in-the-house But, I had some speed issues with it. Here’s how to fix any speed issues by adding a single line to your mysql ini file.
you must add:
to the my.ini file in C:\progam files\mysqlXXX\
in the [mysqld] section
Restart mysql after this.