Microsoft Visual Studio LightSwitch gives you a simpler and faster way to create high-quality business applications for the desktop and the cloud. You can extend the functionality of LightSwitch by creating extensions using Visual Studio 11 Professional Beta, the Visual Studio 11 Beta SDK, and the LightSwitch Extensibility Toolkit for Visual Studio 11.

The toolkit provides project types for creating new LightSwitch Extension Libraries and includes templates for creating the following LightSwitch extensions:

LightSwitch Business Type
LightSwitch Control
LightSwitch Data Source
LightSwitch Screen Template
LightSwitch Shell
LightSwitch Theme

More information regarding these extensibility points can be found here.

Requirements

The following pre-requisites are required in order to create LightSwitch extensions.

Visual Studio 2012 (Professional, Premium, or Ultimate edition)
Visual Studio 2012 SDK
Visual Studio LightSwitch Extensibility Toolkit

Installing the Toolkit

Download and extract the LightSwitch Extensibility Toolkit .exe file to your local machine.
Follow the instructions in the Readme that is extracted to disk.

Launch Visual Studio, and LightSwitch Extension Library project templates will be available under the LightSwitch/Extensibility node in the New Project Dialog. Resources for learning how to build LightSwitch extensions are availablehere.