When a password protected website is accessed using Internet Explorer, it offers the user to remember or save the user credentials. In case if you want to find or recover the saved username and password you can use IE PassView tool. This is similar to the find saved password in Firefox.
IE PassView is a neat and simple tool and can be downloaded from here. After downloading, UnZip the files and copy it to your local machine. Click on the iepv.exe to launch the IE PassView application. The application would instantly display the list of sites with their user credentials as shown below.
This would contain the User Credentials stored as part of Auto Complete as well as Password-Protected Web Site.