I love my new Macbook, it runs Photoshop and Painter way faster than my old G5 iMac, but the small monitor can get a bit annoying, especially when trying to paint on larger canvases. I want to use my old Mac as an external monitor, but I'm not sure what type of cables I need to get. Both the Macbook and iMac have a mini DVI port, but I've searched and can't find a mini DVI-to-mini DVI cable anywhere. How can I do this? What kid of cable(s?) do I need? Thanks.