How install openGL on OS x

I ' ve found opengl on the Mac site but when I install it, it shows a message saying that I need os 9.1 or earlier (on the Readme they say that it run on os 9 or newer). WHY?

[OneSadCookie]

OpenGL is already installed on MacOSX.

But you need to install the developer tools to use the API, there are a ton of good opengl programmin with OSX on the apple dev site