American-British and British-American Dictionaries in the Yahoo! Directory

English to English
American English to British English dictionary, showing differences in spelling as well.
www.geocities.com/Athens/Atlantis/2284
Very Best of British, The
Fun look at the differences between U.S. English and U.K. English. Written by a Brit who lived in Tossa Lane, Texas.
www.effingpot.com
American-to-British Dictionary
Amusing translation of American words to British English.
www.travelfurther.net/dictionaries
English-to-American Dictionary, The
Selection of words aimed at helping Americans keep themselves out of trouble when traveling across the pond.
www.english2american.com