You can download the MSDE database engine from Microsoft. We recommend you search their site for the most recent version. Here are several links to try:
SQL Server 2005 Express Edition
http://www.microsoft.com/Sqlserver/2005/en/us/express.aspx
SQL Server 2005 Express Edition Download
http://www.microsoft.com/Sqlserver/2005/en/us/express-down.aspx
SQL Server 2008 Express
http://www.microsoft.com/express/sql/download/
Iron Speed Designer System Requirements
Production Application System Requirements
Application User System Requirements
.NET Framework 3.0 Compatibility for Iron Speed Designer
Activating and Deactivating Iron Speed Designer
Offline Key Request of Iron Speed Designer
Offline Activation of Iron Speed Designer
How to Check Your MDAC Version
Running Iron Speed Designer Remotely