This link described the express editions.
And from <a href="http://lab.msdn.microsoft.com/express/faq/default.aspx">this</a> FAQ:
The Express products are designed for hobbyists, students, and novice developers. As such, they lack the full breadth of features found in higher-end editions of Visual Studio and are designed specifically for scenarios common to the hobbyist, student, and novice developer. Each Express product includes targeted documentation that will help the beginning programmer quickly learn the concepts required to build more advanced applications. The user interfaces are significantly streamlined to ensure that extraneous features do not interfere with the learning process. The fundamental idea is that the Express products will guide the novice carefully so they are successful and gain confidence early in their programming career.
Starting with ASP.NET 2.0? Look at:
Programming Microsoft Web Forms