change font size through script?

i have this

 public Font                m_font;
 if ( m_font )
     GUI.skin.font = m_font;

and later on

GUI.Label(pos, "" + m_weaponSystem<em>.GetMaxAmmo() + " / " + m_weaponSystem*.GetAmmo());*</em>

but for the life of me find the code to change the size of the font via code?

You have to create a [GUIStyle][1] and assign it to your label:

GUIStyle myStyle = new GUIStyle(GUI.skin.label);
myStyle.fontSize = 12;
GUI.Label(pos, "" + m_weaponSystem<em>.GetMaxAmmo() + " / " + m_weaponSystem*.GetAmmo(), myStyle);*</em>

_*[1]: http://docs.unity3d.com/Documentation/ScriptReference/GUIStyle.html*_