Microsoft has detailed its Xbox Live Arcade extensions for XNA at the GDC08 XNA Developers Day.
The extensions are designed to help developers write fully-fledged Xbox Live Arcade titles using the XNA managed framework, exposing functionality that is hidden to the public out of necessity - such as achievements and TrueSkill rankings - and allowing developers to use the XDK's debugging tools and Xbox 360 developer units in lieu of regular retail machines.
The new features added include leaderboards, ranked matchmaking, the ability to display game status on a friends list (known as 'rich presence'), game invites, achievements and extra TCR compliance functionality.
The extension is structured in Visual Studio as a third profile alongside Xbox 360 and Windows, with a project converter available for games that have already begun life on other platforms. The leaderboard, rich presence and Achievement functionality is encapsulated in several new types, while other Xbox Live features are exposed through expansions of existing types.
The Xbox Live Arcade Extensions for XNA are set for a late April or early May release.