I'm trying to figure out how to "tile" 9 TV sets.  In other words, I
want to stack the TVs in a 3x3 grid, send one picture signal to all 9
sets from a single DVD player, and have each TV display 1/9 of the
total image, so that the image spans all 9 sets.  How do I wire the
TVs together in order to achieve this effect?  And can this be done
with regular TV sets, or does it require special or modified TVs?

Display walls do not generally use television sets, unless they are
capable of functioning as computer monitors.

You might find these articles interesting:

http://www.ncsa.uiuc.edu/TechFocus/Deployment/DBox/

http://www-graphics.stanford.edu/software/wiregl/docs.html

http://research.microsoft.com/~yuqunc/papers/cga00.pdf

http://citeseer.nj.nec.com/chen00software.html

Hi  floridaguy-ga,

  While I totally agree with pinkfreud-ga that you need to have the computer
input capability with a TV for such applications. But you could still drive
the  stack of TV's with cheap video adapter cards with video output and a
combination of linux operating system. In the event that your TV's lack a
video input, you could consider using a multichannel modulator to feed the
antenna inputs. Also you might need to construct custom shelving with
large fresnel lenses if you want an almost seamless video wall.
You might find this link interesting:
http://slashdot.org/articles/02/11/01/2324207.shtml?tid=137

Regards
ldavinci-ga

Here's a system you might be interested in reading about (quite expensive, though):

http://www.9xmedia.com/Pages-products/2000%20-%20Xwall.html

This NEC monitor (and a number of others in the same range) support
this functionality internally. They just need a basic splitter to get
a signal to each display, then they do the processing themselves.

http://dv411.com/lcd1880sx.html

Of course 9 of them would be them would be about $12,000 so it isn't cheap.