Check out these Today in History Sites - History.com.
Here's a great site for the best of history websites.
Nifty Documentaries Site: www.freedocumentaries.org
Check out Citizen Joe (one of Mr. Richmond's cool sites) and Politifact (a political fact checker).
General:
AlternaTime (timelines) http://www2.canisius.edu/~emeryg/time.html
History Day http://www.thehistorynet.com/NationalHistoryDay/
History Wiz http://historywiz.com/
History & Social Studies Web Sites http://www.execpc.com/~dboals/
Teacher's Oz History Kingdon http://members.aol.com/Tchrfromoz/frames.html
Geographia http://www.interknowledge.com
Life Magazine's Top 100 Events of the Last Millennium http://www.pathfinder.com/Life/millennium/events/100.html