Microsoft is in full compliance with the law, which seem to state that every single karaoke game ever released must offer Avril Lavigne's Complicated. So there shouldn't be anything that holds up the game's November release.
If you pre-order the game, you'll receive a voucher that grants you one new song a week for two months. Songs will be selected by the Zune team. Hopefully they won't all be Duffy songs.
Check out our game page for the full song list.