Found a very nice approach for localizing adobe flex application. I am attaching a very basic sample [Download] to show that. This approach uses babelfx for localization.
Go to URL http://www.babelfx.org/, http://www.gridlinked.info/flex-i18n-with-localizationmaps-video-tutorial-source/ for more details/documentation/samples.
Once you open the attached project in Flex Builder you might get error related with fr_FR resource. Use copylocale utility to compile fr_FR resource. Follow the steps below for the same -
1) Go to C:\Program Files\Adobe\Adobe Flash Builder 4\sdks\3.5.0\bin
2) copylocale en_US fr_FR
Do post your comments. Thanks