A quick search on MSDN lead me to this:
http://forums.microsoft.com/msdn/ShowPost.aspx?PostID=1153325&SiteID=1
In which the user says that you need to be a registered Xbox dev, but in that same post he/she links to this:
http://www.xboxusersgroup.com/content/view/3247/217/
Which is hanging when trying to connect to the server on my end, but my internet's been dodgey all night.
EDIT: It appears that second link is pretty much worthless.







