This is the free version of SQL Server Management Studio (SSMS) designed to work with SQL Server 2005 Express Edition.
"Microsoft SQL Server Management Studio Express (SSMSE) provides a graphical management tool for SQL Server 2005 Express Edition (SQL Server Express) instances. SSMSE can also manage relational engine instances created by any edition of SQL Server 2005. SSMSE cannot manage Analysis Services, Integration Services, SQL Server 2005 Mobile Edition, Notification Services, Reporting Services, or SQL Server Agent."
The SQL team heard you loud and clear on the original management tool for express. This one definitely has more features. I think you'll like it! It's a "lite" version of the same tool that comes with the other editions. If you already have SSMS installed, then this install won't work. You already have everything that the Express version has.
Download it here.