The Windows Live Agents team blog released new Windows Live Agents 5.1 SDK. This is also apparently the last version of the SDK and Microsoft will be discontinuing support for the product in Summer 2009. Please use http://agents.live.com/ to download SDK. This version of WLA provides a number of features that allow for better and more intuitive agents development experience. As always we highly recommend you read the release notes about all new features and use help documentation provided with SDK for any question on usage you might have.