Hi there, I've just submitted an en_AU locale for the Flex SDK: https://issues.apache.org/jira/browse/FLEX-16
There's only about 20 or so changes from the en_US locale file - including default date format (ie DD/MM/YYYY not MM/DD/YYYY). In a perfect world we would have an en locale and only have the changes listed in the en_AU local (or other english locales that get added) but not sure how that would be achieved with the current build ant script. I may of missed a few items but it's a good start. There's also a few (4 or so) spelling errors in the current en_US locale .properties files. I can provide patches (and enter a JIRA bug) if anyone is interested and wants these fixed/documented. With minimal changes (phone format and currency symbol would be all I think) it could be converted to an en_GB locale. Thanks, Justin