I have one of the original Apple 22″ Cinema Displays. These monitors use the Apple Display Connector (ADC), which bundles together DVI video, USB, and monitor power into a single cable. It was an interesting idea (presumably derived from/inspired by the way NeXT cube displays worked), but since it wasn’t an industry standard, only Mac video cards had the connector, and only on desktop systems like the PowerMac G4.
If you wanted to connect an ADC monitor to systems that had DVI video output (like the PowerBook G4, and later MacBook Pro), you needed a special adapter that split the ADC into DVI, USB, and provided power. Initially, the DVIator from Dr. Bott was the only affordable solution, so I bought one. It’s served me very well over the last 7 years, and Dr. Bott even replaced mine once when it didn’t work with my aluminum PowerBook G4.
Apple has once again changed their preferred laptop display connector, and now uses the Mini DisplayPort format. MDP provides a teeny connector that can still drive 30″ monitors and the latest versions can also output audio (like HDMI).
Unfortunately, this means that unless you have a Mini DisplayPort monitor (Apple sells one), you need an adapter to connect your monitor to a MDP laptop. For those with DVI monitors, Apple sells a Mini DisplayPort to DVI adapter, which solves the problem. However, I found that adapter does not work with the DVIator, confirmed by this Apple Support forum post, another at MacRumors, and an email from Dr. Bott support. Based on the forum posts, apparently the Apple ADC to DVI adapter ($99!) does work with the MDP to DVI adapter, but I haven’t tested that myself yet.
So, bottom line: if you have a DVIator, an ADC display, and a computer with MDP output, you’ll need to either buy the Apple ADC to DVI adapter (in addition to the MDP to DVI adapter) or buy a new monitor. Bummer.