i tried google and there were several different results
http://www.xboxmp.com/Game/Xbox-360/Green-Day-Rock-Band/2795/
http://www.co-optimus.com/game/1508/xbox-360/green-day-rock-band.html
http://www.extremegamer.ca/multi/reviews/greendayRB.php
and is listed in Link Game Rooms.
That's why I asked