How to to use the Content Query Web Part for exposing different content onto a central page. The solution will be made up of a top level publishing portal with various different types of private and public sites and site collections that will exist underneath. In this post we want to take you through a step-by-step look at exposing the content into a CQWP.
To do this, you insert the Content Query Web Part. This Web Part can be inserted on any Web Part Page, but it can also be added to a page layout from which publishing pages are created. By adding the Content Query Web Part to a page layout, you can make the results of the query appear on every publishing page that is created from that page layout.
Start here the Interactive Flash Tutorial
Additional Reading from Microsoft:
Display data from multiple lists with the Content Query Web Part