I found a British <--> American dictionary:

http://www.peak.org/~jeremy/dictionary/dict.html

-- Richard Manahan (rjcyclesk8@hotmail.com), December 31, 2000

Answers

Here's another one, it may be better:

http://www.peevish.co.uk/slang/frames.htm

-- Richard Manahan (rjcyclesk8@hotmail.com), December 31, 2000.