E.L. Easton English Online
The website comprises Materials for Teaching and Learning. There is a wonderful section called ENGLISH around the World that concentrates on the Varieties of English: http://eleaston.com/world-eng.html. One section concentrates on the Differences between British and American English: http://eleaston.com/brit-eng.html#qz. There is also a huge section on English in relation to several other topics such as Art & Architecture, Country Studies, Currency, Economics, Flags, Food, Geography, Government, Religion, Sports etc., to name a few. Here one can also find course material for English for Special Purposes. The website has a large overview of useful material for learning other languages as well.