Victorian sociologist Charles Booth coloured a map of London to show the wealth of the inhabitants of each street. The University of Michigan has made its copy available on-line.
http://www.umich.edu/~risotto/home.html
An illustrated database of images of prints, maps and panoramas of London and the Thames pre-1870 from print-sellers Motco.
http://www.motco.com/IOL/
Integrated travel map system with bus, tube (underground railway), rail, and walk map. Map includes attractions in and around greater London.
http://www.quickmap.co.uk
Features a zoomable map of central London, only useable by broadband users, as well as a scrollable London Underground guide.
http://www.map-of-london.co.uk