For those who are saying that a they don't understand why a 50" 1080p HDTV couldn't just be used instead of 6 monitors, please understand that resolutions such as 1080p are always 1080p. That is 1920 x 1080 scales up. You have 1920 pixel columns and 1080 pixel rows, regardless of size. So, a bigger set will just have bigger pixels. The aspect ratio is 16:9. If you multiply 1920 by 9, then divide the sum, 17,280, by 16, you get 1080. Most monitors use 1920 x 1200 (as mlopinto2k1 explained), which would be a 16:10 aspect ratio.
Here is a separate article from CNET on the subject:
http://news.cnet.com/8301-13924_3-10350261-64.html?tag=newsEditorsPicksArea.0
AMD is using a resolution of 5760 X 2400 for each monitor. That would be an aspect ratio of 24:10 (so, I'm guessing Samsung would make custom monitors for it).
The math of it is 1920 X 1080 would equate to 2,073,600 pixels per frame--roughly 2 megapixels
1920 x 1200 would equate to 2,304,000 pixels--roughly 2.3 megapixels
5760 x 2400 would equate to 13,824,000 pixels--roughly 14 megapixels
13,824,000 x 6 monitors would equate to 82,944,000 pixels--roughly 83 megapixels.
With the 3D, you are multiply 82,944,000 x 3, which is 248,832,000--which is close to their target of 268 megapixels. I'm not sure if they are doing something a little extra, but the math is off by 20 megapixels.