The Halo Wars demo has found it's way onto xbox live. It is available for download to both Gold & Silver accounts. The demo is approximately 1 GB in size.
Universal link below to queue the download on your console:http://marketplace.xbox.com/en-GB/games/offers/0ddf000a-0000...
Halo Wars is set to release on February 27th
in the UK and March 3rd
in North America.