The Analog Devices offer a line of inexpensive RGB to PAL/NTSC
     converters. The one mentioned below is probably the same one,
     I used for my project, a few weeks ago - AD722. It works OK
     and the external circuit is quite simple. It requires both sync
     from the source. Swapping NTSC to PAL requires :-) changing the
     crystal.

     I paid it some 3$ each (CAD)

     for more (pdf files), see www.analog.com

     Jarek


     >Hi All,
     >
     >Since many people want this VIDEO.ZIP file and various servers where
     >it is located are down or busy, I have prepared an automatic EMAIL.
     >
     >Send a message to me with the subject line, "GET VIDEO.ZIP" You will
     >receive VIDEO.ZIP. The automatic EMAIL will be disabled after a few
     >weeks. (Stuff like this slows my system down.)
     >
     >Also, I have researched getting color NTSC video using a PIC and some
     >support chips. I found an IC from Analog Devices that takes RGB video
     >and converts it to NTSC/PAL. This chip was originally designed to
     >interface to the PC VGA card, but it can be used for other things as
     >well. I don't remember the part #, but it is on AD's web site.
     >
     >Later,
     >
     >Eric Schlaepfer