And now for the ultimate reference site on the Roman Army: Red Rampant. This has got wonderful illustrations for just about everything you can think of relating to the Roman army and its enemies. It’s like an Osprey book, only much, much cheaper.
The battle of Cynoscephalae in 197BC pitted Greek phalanxes against Roman legions. This scenario recreates that battle for the Vis Bellica rules set.
Jeff Jonas has an article on using war machines in Warhammer Ancient Battles. There are some nice pictures of painted Roman war machine models, and a good discussion of their use by the legions.
The Illustrated History of the Roman Empire website is just that — a neat historical site with loads of pictures and interactive map. There is lots of fodder here for historical wargamers.