"

This hosted service represents a new generation metasearch service. It displays results quickly and simply, and gives the searcher unparalleled control over the search experience. These benefits are accomplished through features such as

* simultaneous searching of up to 100 databases almost instantly
* relevance ranking, sorting and merging of records across databases
* processing of returned hits at the rate of 2000 records per second
* faceted searching by resource, subject, author, date or any library-defined element

MasterKey's simplicity and power provide a metasearch experience unequaled by any other metasearch service."

Enabling Federated Search with
Heterogeneous Search Engines

Interesting service from Microsoft.  Looks like they would help indexed licensed content too.  Maybe this is the federated search engine we are really looking for.  Here's what they say: 

Windows Live Academic is now in beta. We currently index content related to computer science, physics, electrical engineering, and related subject areas.

Academic search enables you to search for peer reviewed journal articles contained in journal publisher portals and on the web in locations like citeseer.

Academic search works with libraries and institutions to search and provide access to subscription content for their members. Access restricted resources include subscription services or premium peer-reviewed journals. You may be able to access restricted content through your library or institution.

We have built several features designed to help you rapidly find the content you are searching for including abstract previews via our preview pane, sort and group by capability, and citation export. We invite you to try us out - and share your feedback with us.