Looks like select models, heard it on the radio this morning and currently on their website. The deal seems to be select "last season laptops" over $700, get a free xbox 360 4gb.
Terms are:
XBOX 360 Console
Bonus offer applies only with the purchase of the selected products. Excludes tablets. Not to be used in conjunction with any other offer. Bonus can only be redeemed at the store from which the applicable product(s) are purchased. Bonus is not transferable for a discount, cash or gift card. For a full refund, all items must be returned in their original condition. Terms and conditions apply. Bonus offer ends 27/11/11.
Buy your laptop from somewhere else, and I can almost gaurantee that you will save more than the cost of a 4gb xbox.