One part encyclopedia and one part news aggregate, the SIRS Discoverer and SIRS Issues Researcher from ProQuest are a great starting point for any research topic catering to grades 3 through 12. Definitions and information on current issues, world events, nations, and other topics are supported with up-to-date links to topical news stories for each subject. 

http://discoverer.sirs.com/
http://sks.sirs.com/