Microsoft Surface SDK can now be freely downloaded!
As announced at PDC 2009, the Microsoft Surface SDK 1.0 SP1 has been released for download at http://www.microsoft.com/surface/Pages/Technical/Learn.aspx.
Surface SDK includes the APIs, documentation, and tools to help you develop Surface touch-enabled applications on your workstation. No Surface unit is required for development and testing, a Surface simulator allows you to test multi-touch input – just attach as many mice as you want touch points – and 2D-barcode / tag recognition.
Before you download the Surface SDK, make sure you read the Setting Up a Development Environment article to learn about the hardware and software requirements for developing Surface applications on a workstation.
Make sure to follow the Surface blog if you are interested in Surface development.