Multimap is a UK based company but provides great street maps for Germany and other European countries.
To find a particular location or street map Multimap Germany is hard to beat.
Multimap Germany provides detailed maps of Germany and you can navigate from there to maps for most other European countries. The maps for the UK, and for London in particular, are excellent.
Other useful map sites providing German maps are: Mapquest, Yahoo, Google maps, Via Michelin, and Mappy. Microsoft own Multimap but have maintained the Multimap name.