Just bought a £99 wii at Asda and saw the Xbox arcade on the same shelf for £89.
Seems a good deal. There was mention that the Wii deal was only for the 1st and 2nd of January, so this might be the same, in which case you may only have a few hours to take advantage.
However checkout girl on the service desk at my local asda hadn't head that the deal was only for the 2 days, so might still be available in the coming days.
I'm assuming this deal is nationwide, just like the Wii deal.