I've been away a while, so I only just found this thread.
Firstly - the TV standards.
NTSC = National Television Standards Commitee, aka Never Twice the Same Colour, used in US and other third world TV countries
SECAM = SEquential Coleur Avec Memoir, aka Something Essentially Contrary to the American Method. Used in France, Russia and related countries.
PAL = Phase Alternating Line, aka Peace At Last. Solves the green faces/ purple trees problems that plague NTSC. Used in enlightened countries
TV vertical resolution is set by the number of lines - about 480 for NTSC, 580 for PAL and SECAM. Horizontal resolution is set by the maximum video bandwidth, about 5MHz for PAL, 4MHz for NTSC. Colour bandwidth is worse. The upshot is that 800x600 is the maximum resolution you can reasonably display on a TV, and even then you need to use large fonts for it to be readable.
There are some variations each format, for more info, look here
Most TV sets are deliberately overscanned - the picture is larger than the "frame". The smaller the set, the more the overscan, and the more information is lost around the edges. To compensate for this, and to make sure that the whole PC display area is visible on the TV, most TV out chips are programmed to uderscan the image, with a black border all round. The TV out chips usually can expand the picture to "full screen" or "overscan" mode, but the standard drivers might not give you the option.
Have a look at tvtool
It's a very useful utility, although it might not work on your hardware (and is nVidia only).
Hope this helps.