Using a Macbook / Macbook Pro with an external monitor and the lid down

Lucky me has a 24" monitor (OK its a Dell so not as lucky as I could be ;) , but I don't like having 2 monitors of different sizes.

For me its better to have the lid down and only use the external monitor.

Anyway I found this KB at Apple that says how to do it:

If you use an external display or projector with any MacBook Pro or PowerBook G4 and a USB mouse or keyboard, you can close the display and still use the computer. Here's how.

(If you want to do the same thing with a Bluetooth mouse and keyboard, see this article.)

1. Make sure the computer is plugged in to an outlet using the AC power adapter.

2. Connect a USB keyboard and mouse to your computer.

3. Connect the Apple video (VGA or DVI) adapter that came with your computer to the appropriate port on the external display or projector and turn the display or projector on.

4. With the computer turned on and your keyboard or mouse connected, connect the other end of the adapter to the video output port on your MacBook Pro or PowerBook G4.

5. Once your computer's Desktop appears on the external display, close the computer's lid.

6. Once the lid is closed, wake the computer up by either clicking your mouse button or by pressing a key on your keyboard.

You should now be able to use your MacBook Pro or PowerBook G4 as you normally would, using your USB keyboard or mouse.

To disconnect your MacBook Pro or PowerBook G4 from the display after use:

When you're finished using your MacBook Pro, MacBook, or PowerBook in closed-lid mode, the internal display will not function when you open the lid until you have properly disconnected the external display. To properly disconnect the external display, put the computer to sleep and disconnect the display cable from the computer. Open the lid and the computer reactivates the internal display.

Some DVI displays, including Apple's aluminum-framed DVI displays, can be unplugged without putting the computer to sleep. If you aren't sure whether your display supports this feature, put your computer to sleep before unplugging the display.

UPDATE: On some Macbook Pros the recent Graphics Update has a bug which prevents this working. Also if you disconnect the monitor you may find that the internal screen does not stay on. Apple say it is a known issue.

UPDATE #2: The 1.5.1 EFI firmware update fixes this issue. Now works fine!