http://www.joystiq.com/2006/12/18/games-for-windows-vista-how-a-new-brand-and-os-will-change-pc-gam/
"For console gamers, especially Xbox 360 owners, the most intriguing aspect of gaming on Vista is 'Live Anywhere.' Unfortunately, Xbox Live awareness won't be built into the initial release of Vista. Instead, it will gradually be tested on the Windows platform via launch titles like Shadowrun and Halo 2. Both these games will be fully integrated into Xbox Live -- Shadowrun will feature cross-platform multiplayer, while Halo 2 will be limited to cross-platform communication (messaging, invites, voice-chat, etc.) -- and will include achievement points (added to your pre-existing Gamerscore); we should note that achievements points can't be doubled for cross-platform titles. If you own Shadowrun for Xbox 360 and PC, you can only unlock any given achievement once (per Gamertag) between the two versions. To enhance cross-platform mingling, certain elements of 360's GUI will be included in Live-enabled PC games, like a version of the 'Guide-button' interface, but the hope is that eventually the core elements of 360's GUI will be offered as a free Windows application, capable of running without a game (
"For console gamers, especially Xbox 360 owners, the most intriguing aspect of gaming on Vista is 'Live Anywhere.' Unfortunately, Xbox Live awareness won't be built into the initial release of Vista. Instead, it will gradually be tested on the Windows platform via launch titles like Shadowrun and Halo 2. Both these games will be fully integrated into Xbox Live -- Shadowrun will feature cross-platform multiplayer, while Halo 2 will be limited to cross-platform communication (messaging, invites, voice-chat, etc.) -- and will include achievement points (added to your pre-existing Gamerscore); we should note that achievements points can't be doubled for cross-platform titles. If you own Shadowrun for Xbox 360 and PC, you can only unlock any given achievement once (per Gamertag) between the two versions. To enhance cross-platform mingling, certain elements of 360's GUI will be included in Live-enabled PC games, like a version of the 'Guide-button' interface, but the hope is that eventually the core elements of 360's GUI will be offered as a free Windows application, capable of running without a game (