IExpress is a technology designed to simplify creation of a setup program. Using the IExpress Wizard, you can create an executable file that runs the setup program contained inside. The setup program can be an .inf file or an executable program. IExpress automatically removes the setup files after installation.
The IExpress Wizard can help you carry out simple installations of your customized package, such as directing whether the computer will be restarted after installation. IExpress uses a Self-Extraction Directive (.sed) file to store information about your package. The .sed file contains information and instructions for the setup package. In Windows XP, Windows Vista and Windows 7, you will find the IExpress Wizard (IExpress.exe) in the System32 folder.
While Microsoft has plenty of information available about this older but still sometimes useful program, you can follow the link at the Petri IT Knowledge base article below to get started with a simple step by step example.
Create Executable Wrappers with IExpress in Windows Vista and Windows XP (Petri IT KB)
IExpress Technology and the IExpress Wizard
Command-line Options and IExpress
Command-line switches for IExpress software update packages