Best place to start for anything to do with sql server is BOL (books online)...you can go to English Query....Overview....for a beginning..

Here's the definition from that page..

Using English Query, you can turn your relational databases into English Query applications, which allow end users to pose questions in English instead of forming a query with an SQL statement.

The English Query Model Editor appears within the Microsoft® Visual Studio® version 6.0 development environment. From there, you can choose one of the English Query project wizards, the SQL Project Wizard or the OLAP Project Wizard, to automatically create an English Query project and model. After the basic model is created, you can refine, test, and compile it into an English Query application (*.eqd), and then deploy it (for example, to the Web).