First World War
Life in the Trenches
An engrossing narrative of the horrid day to day life amid rats and frogs and uncertainty in the trenches of World War I.
Internet History Sourcebooks Project
Fordham University: Modern History Sourcebook: Private Donald Fraser
Contains a first-person primary source account of WWI that focuses on trench warfare and "No Man's Land."
First World War
First World war.com
Site does a good job of giving an overview of most of the key aspects of World War I: the causes of the war, a timeline, weapons of war, etc. As a special feature you can listen to vintage audio of speeches and music of the WWI era.