History of the Atlantic Cable & Submarine Telegraphy
Early cable route maps were often published in the cable history books. Later maps were issued as promotional items by cable companies and government telecommunications authorities.
Map History / History of Cartography - THE Gateway to the Subject
A global overview of the history of cartography, aimed at surfers or scholars, spread over about 100 pages. The logical directory structure makes it easy to retrieve information. The site currently includes over 3,500 carefully selected and annotated links. There are also leads to the collecting of early maps.
The Map Room
The Map Room is all about finding maps, map collections, map-related resources, and material about maps on the web. Anything that fits under that rubric, from medieval mappæ mundi to satellite imagery, and from topo maps to Tolkien, is fair game. The Map Room is aimed at a broad audience. While GIS professionals and cartographers enjoy reading it, it’s intended to be accessible to anyone with nothing more than an interest in maps. The Map Room was launched in March 2003, and has been featured on the Guardian’s weblog, MetaFilter, and dozens of personal weblogs around the world. (Technorati)
Old Ordnance Survey UK Maps
Access to loads of old Ordnance Survey Maps online and Gazetteer
David Rumsey Collection
The David Rumsey Historical Map Collection has over 11,000 maps online. The collection focuses on rare 18th and 19th century North and South America maps and other cartographic materials. Historic maps of the World, Europe, Asia and Africa are also represented.
Online store of current maps to order.
Genmaps is a site devoted to online images of English, Welsh and Scottish maps from their beginnings to the early 20th Century. It is intended to be for the use of historians, educators and genealogists for non-commercial research purposes. Particularly look at their links page, it's huge!