Doron and others have produced a great guides that help in migrating away from proprietary IE features that aren't available in browsers that support and are compliant with web standards.
Stuff like http://developer.mozilla.org/en/docs/index.php?title=Migrate_apps_from_Internet_Explorer_to_Mozillahttp://developer.mozilla.org/en/docs/index.php?title=Migrate_apps_from_Internet_Explorer_to_Mozilla
Does anyone know if similar guides, case histories, or best practices exist for developers that want to migrate away from ActiveX?