A. For users of the Xbox 360, the ability to play online is a simple affair: Games connect to the Xbox Live service and via your gamertag, which is basically your gaming name, you can interact and play online. With PC games this has always been a far more cumbersome affair, with no standard naming across games and no standard set of servers. This is going to change with the LIVE Gaming for Windows Vista.
For users of Xbox 360, one gamertag will be used across both Xbox and the Vista-based Gaming service, with a single common interface across any PC game that will interact with the Live Gaming. This makes it easier to play with the same group of friends no matter what the game title, and that friends list will be consistent on both Xbox and Windows.
It's also believed to have cross-platform gaming support across both Xbox and Windows. Like Xbox, there will be different levels of service but it will be consistent: If you are a Gold-level subscriber on Xbox, then you'll be Gold on Windows; no additional fees apply.