OnMouseDown Create In-Game Popup TextBox

Having the hardest time with OnMouseDown.

Cant get it to work with GuiText or Texture.

Whats a quick snippet of code for this?

Ive searched for forums and only found things relating to Iphone.

Idea:
Player clicks on 3D Mesh+Colliadable : Pops up with information about said Object. OnMouseUp the Textbox Disappears (optional. may have it just stay and refresh when they select a different Box)

Umm. this doesnt even work!

function OnMouseOver () {
   if (Input.GetMouseButtonDown(1)) {
      print ("test!");

   }
}

It works just fine. just copy and pasted it to a script, created a GUITexture, attached the scripted to the GUITexture object, ran it in the editor, right clicked on it and it prints “test” in the console.

Are you attaching the script to the GUITexture? are you running it before clicking on it? Mouse Button 1 is the RIGHT mouse button by the way too.