SQL Server Express is a free, easy to use, redistributable version of SQL Server 2005 designed for building simple data-driven applications. Developers can design schemas, add data, and query local databases, all inside the Visual Studio 2005 environment. If developers need more advanced database features, then SQL Server Express can be seamlessly upgraded to more sophisticated versions of SQL Server.
http://msdn.microsoft.com/sql/express/
SQL Server 2005 Features Comparisonhttp://www.microsoft.com/sql/prodinfo/features/compare-features.mspx
Server Management Studio Express is a free graphical management tool for SQL Express that makes it easy for you to administer SQL Server Express databases.
http://www.microsoft.com/downloads/details.aspx?familyid=82AFBD59-57A4-455E-A2D6-1D4C98D40F6E&displaylang=en
