SQL Server Express can handle multi-user networked apps no problem, although the databases can only be 4GB and it won't handle the same load as the full SQL Server. What you want to do is no different than it would be with the full SQL Server. You need to install SQL Server Express on your server and make sure you enable remote connections. You use Management Studio Express to create the database and then your application simply needs to specify the appropriate connection string, the format for which you can find using the link in my last post.