Microsoft Visual Studio LightSwitch gives you a simpler and faster way to create high-quality business applications for the desktop and the cloud. Professional developers can extend the functionality of LightSwitch by creating extensions using Visual Studio 2010 Professional, the Visual Studio SDK, and the Visual Studio LightSwitch 2011 Extensibility Toolkit. The toolkit provides project types for creating new LightSwitch Extension Libraries and includes templates for creating your own themes, shells, business types, controls, screen templates, and data sources.
You can access the toolkit plus walkthroughs, samples and documentation here on the Developer Center:
Please make sure you follow the instructions carefully for installing the toolkit and the prerequisites. Also check out the LightSwitch Extensions from our featured partners.