This IIS Manager overview explains why IIS7 has an entirely new user interface, and then goes on to describe the look and feel, feature delegation, interaction with configuration, and remoting. This document was written for Longhorn Server. Windows Vista may not have some of the functionality/features discussed in this document.

The Internet Information Services (IIS) Manager is entirely new in IIS7. 

Why did it have to change?  So glad you asked – here are a few of our top reasons: Read more here.