General History Links
University of Kansas (very useful): 
   Scholars Guide to the WWW
   History Website
Journal Storage, a great collection of back issues of scholarly journals, online and searchable.
Liberty, Equality, Fraternity: Exploring the French Revolution (http://chnm.gmu.edu/revolution)
History Matters: The U.S. Survey Course on the Web (http://historymatters.gmu.edu)
ECHO: Exploring and Collecting History Online--Science & Technology (http://chnm.gmu.edu/echo)

World History (-0x's)
World population Resources Page
Global Problems Website
Online Global Problems Reader

Ancient History (-1x's)
Perseus Project

Medieval and Early Modern European History (-2x's)
The Haskins Society
Amsterdam Medieval Society
Labyrinth Homepage
Medieval Sourcebook
Medieval Women

Modern European History (-3x's)

American History (-4x's)

Military History
De Re Militari (medieval military history)

Teaching and Learning
US and World History Standards