But really what is it you ask?
Plasma Monitors are basically a few pieces of glass glued together with tiny pockets of xeon(used in florusent bulbs) and neon (over used in Las Vegas Signs) gases. Then the glass panel is connected to some electronics in the back and viola, you have a TV that is 2-4" deep that you can hang on the wall above the fireplace. I will address the technical aspects below but rest assured, these televisions work with all your existing equipment and function just like that bulky Tv you might have now.
Myths and Half Truths about Plasma.

I thought I had heard it all until one day a nice couple came into the store to buy a new TV. Then upon talking with them the man said he was not interested in plasma because you had to have them refilled with plasma every few years and it was expensive. I did not laugh becuase this was just another bogous big box employee's training comming through (or lack there of). Anyways, Plasma TV's are rated from 20k-60k hours of use to half brightness. For most consumers, this is 8 to 20 years depending on use. Chances are if you have an old school TV it will be half as brite after 8-16 years as well but you still watch it. You can not refill plasma screens, however you can hang them upside down, diagonal, or lay them flat on the ground. They are made with glass like a regular TV so you cannot drop them either. Plasmas do work in higher elevations, but not too high. If you do live in a area over 2500 ft, check with your retailer to see whether there might be an issue. If they do not know what you're talking about then find another retailer. There are plasmas that will work at 10k ft and above, but some of the chinese imports will produce a buzz if you take them too high. There are two downsides to plasma, first is that they can burn like a traditional TV and are a bit more senstive to it. What I mean by burning is the phospher on the inside of the glass can burn out, so to speak, and result in an image staying there forever. I have seen this in airport installations where the same image is always on the screen and changes very little or not often. The second is price. Plasmas are expensive; $2500-$25,000 is their price tag. But they are well worth it in my opinion if looks or space is important. People spend thousands of dollars on furniture everyday, but then spend $300 on their TV. I do not get that one. Anyways, some people are saying that Plasma will be replaced by LCD (see LCD) in the near future. The reason this is likley to happen is for price reasons more than any other issue. LCD's current ly do not preform as well, and in larger size formats they cost more. But LCD's will go down in price and up in image quality, even so, plasma is here to stay for the next 5-10 years. But if you are thinking of waiting for LCD then you might as well wait for OLED (5-10 years), or better yet wait for Motorla's nano organic thinga majig, that will be here in 10-15 years. One buys Plasma becuase they want a thin TV that gives them the best picture, that's all, it is that simple.
Tech Stuff

Plasma displays have lots of pockets or cells that are filled with XEON and NEON gases. Each pocket is refered to as a pixel or picture element. Plasmas have typically come in one of two configurations for pixels. The first is 852x468 WVGA, and the second is 1366x768 WXGA. There are several others, but for the purpose of this article we wil just discuss these two formats. While Pixels are important, in the world of video reproduction they are less important than several other factors, unless you are hooking up a computer. Also, there is much debate over what constitutes HD vs ED plasma. Most agree that WVGA is not HD but ED, however, I would argue that in the 32 and 42 inch that it is hard to see the difference unless the units are side by side. I would argue until the cows come back to the old ranch that several other specs are more important at this point. And perhaps the most important part is the scaler. The scaler is the electronics that takes your DVD or HDTV source and maps it to the p ixels to create the moving picture. A good scaler will cause an ED plasma to look a lot better than a bad scaler in an HD panel. I have found most people agree with me on this issue. However, a scaler is not as important when you hook up a computer to it and surf the web. Then and only then is Pixel count important. The next important spec that matters is the contrast ratio. The higher the number, the better it's going to be in general. This assumes you can trust the manufacturer's supplied numbers. And believe me some manufacters will lie. So it is important that you see the plasma or someone you trust sees the unit before you decide to buy. Then you have the various classes: Class A, B, and C. Just trust me when I say you want class B, otherwise you might get a sunburn (Just kidding). Class B emits less infra red so it will not interfere with your remote control.