The Matrox DualHead2Go is another solution for adding additional monitors to your laptop. The DualHead2Go connects to your existing VGA-out port on your laptop and splits it into two VGA ports. With the included software you can use your existing laptop screen and the two additional monitors. You can extend your desktop onto the three screens for maximum productivity.
The VTbook DVI PCMCIA Card allows you to add a DVI port to any laptop through the PCMCIA (CardBus) slot. The card also includes a DVI to VGA adapter if you would like to add an additional VGA monitor rather than a DVI-enabled monitor.
The VTBook will “play nice” with your built-in VGA port on your laptop allowing you to use three displays (including your existing laptop screen). Your desktop can either be mirrored to show the exact same thing on all the displays, or you can extend your desktop with the included software.
For even more desktop space you can add an optional dual-head adapter which will convert the DVI port on the VTBook to 1 DVI-out and one VGA-out, allowing you to use 4 displays total.