Ancient Atlas - About.com
A collection of annotated links for online maps of the ancient world and from antiquity.
http://ancienthistory.about.com/library/bl/bl_maps_index.htm

Classical Atlas Project
The Barrington Atlas is a reference work of the ancient Greeks and Romans, the lands they penetrated, and the peoples and cultures they encountered in Europe, North Africa and Western Asia.
http://www.unc.edu/depts/cl_atlas/

Historic Atlas Resource - Europe
Historical and Cultural Atlas Resource
http://darkwing.uoregon.edu/~atlas/europe/maps.html

Perseus Atlas
Map server gateway offering browsable maps of named places from the ancient world. Allows overlays of Roman provinces and modern boundaries, and comparisons against modern features and population centers.
http://www.perseus.tufts.edu/cgi-bin/patlas

Rome: Map Resources
Maps of the Roman Empire
http://www.dalton.org/groups/rome/RMAPS.html

The Interactive Ancient Mediterranean Project
"IAM: an on-line atlas of the ancient Mediterranean world ... "
http://iam.classics.unc.edu/

The Roman Empire
The Roman Empire at its Greatest Extent
http://www.acs.ucalgary.ca/~vandersp/Courses/maps/basicmap.html