Separated by a common language – Observations on British and American English by an American linguist in the UK – looks like a very useful weblog.
I suppose discussion of the differences between BE or BrE and AmE has exploded as a result of the Internet. It’s usually uninformed discussion. This blog by Lynne could be a good place to clear up confusion.
It comes via languagehat, where I find an American having to tell an Australian that -ize was not invented by Noah Webster (a book review in the MDÜ, by a German, criticized the book for using -ize and thus ‘mixing up’ AmE and BE spelling).