We've included the Language Token in the Flex skin. This automatically appears if you install multiple languages to your DotNetNuke portal. If you don't, it won't appear.
The default flag icons supplied with DotNetNuke aren't the prettiest, so we've included our own set as an extra with the Flex skin!
Simply upload them to your DotNetNuke portal to replace the default icons. Full instructions are included in the manual.