Armamentarium: the Book of Roman Arms and Armour: An illustrated source book about Roman military equipment
Caesar's Commentaries on the Gallic and Civil Wars: Julius Caesar's accounts of the Gallic and civil wars - extensive text file 58-47 B.C.
Legio III Augusta: An operational history of the third Roman legion by John J. Hartwell.
ORB: The Late Roman Army: Article describing changes in the Roman army during and after Diocletian (284-305 A.D.).
RedRampant.com: Information on the Roman army, the legions and various campaigns. With pictures of uniforms, shield patterns, and armor.
Roman Expansion to 133 BC: An essay by Sanderson Beck.
RomanArmy.com: Resource for Roman military studies, including an image database for Roman soldier's grave stones with Latin texts, and a discussion group for archaeology and reenactment.
The Glory That Was Rome: An extensive look at the development of the Roman Army from the late Republic to the height of the Empire. History, artillery, siegecraft, wars, and other subjects discussed.
The Landings of Caesar in Britain: Overview of Ceasar's landings and attempted conquest of Britain, 55-54 B.C.
The Roman Army: Describes Roman military organisation from the early Republican period through to the late Byzantine period.
The Roman Army In Caerleon: Fortress for one of the 30 legions of the army.
The Roman Army in the First Century CE: A writing according to Josephus.
The Roman Army in the Late Republic and Early Empire: Covers the Roman army from about 70 B.C. to 30 A.D., includes descriptions of key officer ranks, formations and military buildings/fortifications.
The Roman Army Page: Information about Roman legions during the imperial era, including organisation, funding, privileges of ordinary soldiers, plus links to other sites.
The Roman Way of Declaring War: Highly needful to observe all the necessary formalities in beginning hostilities according to Livy.
Victori - The Roman Military: A resource on the weapons, tactics, and history of the ancient Roman military.