I recently saw a demo of Samsung’s new 3D HDTV; the 3D effects were excellent and of course much better than the red/blue lens method. But looking at the screen sans 3D glasses, I didn’t see anything about the display that seemed all that special. By that I mean I think a DVD would be easy to produce with the requisite dual-images or whatever for display on any HD monitor. Why the need for a special TV?
AFAIK, in a nutshell, what you are actually getting is a screen and glasses that switch in sync. You get a left eye image 60 times a second, and a right eye image 60 times a second, and the glasses only let you see one or the other at a time. This all happens faster than your eye is able to detect. As this is the dope, I hope someone with more knowledge than I comes along shortly 
Right, the source of the video stream (whether a PC or a blue-ray player) needs to be outputting a 120hz stream. you need a TV (and a connection) capable of handling that bandwidth. most current 120hz Tv’s can’t do 3d by the way. They can’t handle that type of bandwidth, instead what they do is interpolate frames into standard 60hz streams.
In addition to the high speed screen & shutter glasses systems there can be passive polarized systems. These have special screens, they use two screens on top of each other if I’m not mistaken, where each screen emits light that can be blocked by a different filter so you have one over each eye.
And there’s also systems where the 3d can work with out glasses. But I can never remember how they are supposed to work.
Yeah. The key is having a display device that handle double the normal number of frames per second.
Another interesting thing you can do with a 3-D TV is let two viewers watch different programs at the same time on the same screen. Instead of configuring the glasses to alternate between the left and right eyes, you set them up so both eyes see the same frame, but you alternate frames between viewers. One person needs to wear headphones though … .
You also need some way for the TV to communicate with the glasses, so they can synch up. Nowadays, that’s probably Bluetooth.
Ignorance fought! Thanks, all.