MSDE Is Being Replaced!

In addition to the Express development products, Microsoft also released a beta for SQL Server Express Edition. This is a low-end version of SQL Server that can be used for small scale systems and such. This version of SQL Server replaces the Microsoft SQL Server Desktop Engine (MSDE) that was previously made available to developers. Like MSDE, SQL Server Express Edition will be free for use and redistribution.

http://lab.msdn.microsoft.com/express/sql/default.aspx