English is not my native language - I've learned it since I was a kid at school. I thought I know it quite well until I've tried to watch British videos and listen to native British speakers. Since then British way of speaking became a subject of slight fascination to me, and so I ask - can you name some good resources that almost fully (!) cover differences between different kinds of English, that teach you specifically British/Canadian/Australian English (pronounciation/words/phrases/slang etc.), assuming that you have some background in English? Resources that cover to some degree history of British English language are welcomed as well.
Addendum: The title might be confusing, "American" part specifically - I've written my question like this because I think (and some English teachers here also say so) that the kind of English that I know and see everyday on the Internet/media is the most popular kind - American English.