I got the Ergotron LX Wall Mount for my 22" widescreen Planar monitor about a month ago. It works beautifully. Ergotron's website will tell you if your monitor is compatible with their mounts.
The LX wall mount is very stable. I can move my monitor anywhere in a hemisphere that comes about 22" off the wall. The tensions on movement in each direction is adjustable. It saves some desk space, but the best part is that now I can watch movies on my computer while I'm laying in bed (I just turn the monitor to the right).
The retail price is a little high, but I got mine pretty cheap on ebay. It's definitely a quality piece of equipment from a quality company.