UK road maps and direction services
Bing MapsBing Maps have standard road maps, a London street map and ordinance survey maps online for you to use. The service can provide directions for driving, walking or other transit as well as a search facility for local shops and services.
Google MapsThis site from the Google stable includes maps and satellite images of UK locations, along with directions for any journey you wish to define.
Streetmap.co.ukA map site that will produce a map of anywhere in the UK when given either the place name, postcode, tel code, OS grid, or even the lat/long coordinates. There are seven different scales to chose from.