Apple released iOS 6 today and the update is now starting to hit the iPhone, iPad, and iPod touch. Be patient as not everyone is seeing the update, and if you are getting the update, it may take time to download and install.
iOS 6 brings a new Maps app, Facebook integration, shared photo streams, Siri improvements and more. You can download the update over the air by going to Settings > General > Software Update. If you have iTunes and a cable, you can also connect your iOS device to your computer and download the update manually.