Search Area
Problem
The users need to find a page
Solution
Use a dedicated area with different kinds of search functionality.

From
www.att.com
Use when
In addition to the main navigation scheme, the web site has secondary functionality to search for information. Such sites are typically medium to large sites. There may be several kinds of search-related functionality on the site. The search functionality is not the main way to access the information, it has a secondary role.
How
Group the different kinds of search functionality and place them in a small rectangular area. The area is placed in a prominent position on the page but is not masking the main navigation. Use a combination of a
Search Box together with a
Site Map,
Site Index,
Search Tips or
Advanced Search.
Why
By combining all these search related functionality, the Search Area is THE place for searching and users only need to go to one place on the page. Alternatives and help is provided in a coherent way.
More Examples
Apple uses a search area with sitemap, tips and options.