If you would use GUI instead of GUILayout you'd have to provide the exact screen-space rectangle of the control. You can also position GUI elements using GUILayout using GUILayout.BeginArea which also takes a rectangle in screen-space as one of its parameters.

Just read this: http://unity3d.com/support/documentation/Manual/Game%20Interface%20Elements.html Or for a quick reference this: http://unity3d.com/support/documentation/ScriptReference/GUI.html and this http://unity3d.com/support/documentation/ScriptReference/GUILayout.html and all the other script reference pages as required. I mean...it's all in the manual :D