How can I call an URL?

Maybe this is a silly question, but i have like 3 days using Unity, I made a great 3d place, but now i want to call a webpage

I know how to setup a GUI button

function OnGUI () {
    if (GUI.Button (Rect (380,10,150,50), "Visit WEBPAGE")) {
    	// what do i have to put here?//
    }
}

Can someone help? is there a way to call a pop up also?

if you want to open a URL in your browser use Application.OpenURL:

Application.OpenURL("http://www.example.com");

if you want to get the HTML code of the page use www class. if you want to render the page in your scene you should use some internet service that turns a webpage to a JPEG or PNG image and send it back to you. if you want a full 3D browser in your game vote for this please