ISO is the most commonly used format around the world and it had always required support of third part tools when you go to burn it. Previous versions of Windows never understood WHAT ISO was or you can say the format was not supported.
But with Windows 7 , It has native support for burning an ISO file to your CD or DVD. In case you are wondering how you can burn it to yoru DVD its simple. Just double click it , Choose your Writer or burner and Make final selection if you want to verify or not. This is like Just Do it approach. Give it a try.