Dan--No, there isn't any loss of resolution. At one point I was looking into hooking my 20" Cinema Display to my PC and found a variety of adapters for $100-$150 to convert DVI outputs to an ADC connection. I think the biggest issue was the loss of monitor adjustment functions because they're software based.
The new Cinema displays have brightness controls on their sides, so they're basically 100% compatible with PCs. Adjusting the brightness was the only problem with the last generation displays--they default to the brightest setting without the software.
The Nvidia Detonators definitely allows you to control brightness/contrast/saturation/gamma in software. So even the old Cinemas could have their image adjusted on a PC... to even a greater extend than what you could do on Apple's software.