Talk Tidy - http://talktidy.com/ A humorous dictionary of the English dialect used in and around the valleys of South Wales.
English Accents and Dialects - http://www.collectbritain.co.uk/collections/dialects/ Extracts from the Survey of English Dialects and the Millennium Memory Bank document how the English spoke and lived in the 20th century.
Norfolk England Dialect - http://www.geocities.com/Heartland/Acres/5564/dialect.html Pauline Dodd's page about the intricacies of the Norfolk dialect, including a wav file of Keith Skipper, journalist with the Eastern Daily Press and author of 'Larn Yourself Norfolk'.
Whoohoo.co.uk - http://www.whoohoo.co.uk/ Translate your English phrase, email or text message into a variety of different British dialects including Geordie, Cockney Rhyming Slang, Irish, Brummie, Scottish, Scouse, Posh and Ali G.
Yorkshire Dialect Society - http://www.ydsociety.org.uk/ Scholarly society meets four times a year. Publishes an annual journal, "Transactions of the Yorkshire Dialect Society."