SQL Server 2005 Express Edition

Microsoft SQL Server 2005 Express Edition is a free, redistributable version of SQL Server 2005. It's easy to use and designed for building simple data-driven applications needing up to 4 GB of data, but scalable so that it can easily be upgraded to the more advanced versions of Microsoft SQL Server 2005. The SQL Server 2005 Express Edition is the replacement for the Microsoft SQL Server Desktop Engine (MSDE), which won't be supported on the Microsoft Windows Vista operating system. Runs on Windows.