GUI.ScrollTo

// Draws a Scroll view with 2 buttons inside.
// When clicked each button it moves the scroll
// where the other button is located
var scrollPos : Vector2 = Vector2.zero;

function OnGUI () {
    scrollPos = GUI.BeginScrollView( Rect (10, 10, 100, 50), scrollPos, Rect (0, 0, 220, 10));

    if( GUI.Button ( Rect (0,0,100,20), "Go Right"))
        GUI.ScrollTo( Rect (120,0,100,20));

    if( GUI.Button ( Rect (120,0,100,20) , "Go Left"))
        GUI.ScrollTo( Rect (0,0,100,20));
   
    // End the scroll view that we began above.
    GUI.EndScrollView ();
}