Despite this project being, for the most part, software driven, it still needs hardware to work. As described on the FAQ, there are a number of alternatives:
- you can use an RGB monitor that handles TV frequencies (15Khz), like Commodore Amiga' monitors;
- a TV with RGB inputs, common in Europe, using the SCART/EURO-AV/Peritel standard 21-pin plug, or some other method;
- build a RGB to composite or S-Video circuit, based on one of the chips mentioned below; or,
- get someone else to do it for you; and finally,
- buy a commercial board. More below.

Of the five, the SCART cable is the easiest. Basically, all you need to do is connect the RGB lines together from the VGA output to the SCART input. To get composite sync, you'd need to do some simple circuit, but I've been told more than once, that you can simply join the HSync and VSync wires together... For detailed information, you can access Tomi Engdahl's site at http://www.hut.fi/Misc/Electronics/circuits/vga2tv/cindex.html.

As I said above, you can also try to get your hands on a ready made RGB converter. There are sites on the web that carry this information, but I was also alerted to the fact that Analog Devices has evaluation boards you can buy, which besides converting the signal also work as video switches, so you can use your monitor or your TV at will, without having to switch video cables all the time. Really neat. Prices start at USD$125 for the AD724-EB. Check the AD724 page, link below.

For PAL TVs, the aspect ratio of all modes is the same as with a VGA monitor. The exception comes from 320 pixel wide modes (except standard mode 13h) which, if not using a 7Mhz dot clock, appears skinny, due to the high data rate (12.5Mhz). I don't know how it looks on a proper NTSC TV, but when using NTSC timings, the TV's I've used show a streched picture. Maybe that's because the TVs are "used" to having 576 displayable lines instead of 480. Maybe someone can shed some light on this.

Regarding borders and stuff, things get a little bit more complicated. I'll be using PAL examples when needed.
Up to, and including 800x600 resolutions, all lines are displayed, when interlace is used. For modes with less than 300 lines (arbitrary value), which include 240 and 200 line modes, interlace is not used. Vertically, only modes with more than about 540 lines, have vertical overscan. Due to having a correct aspect ratio, they also have horizontal overscan. This is the main reason to use these modes: you get a picture as close to broadcast TV as possible. Other modes have a more or less bigger border around the picture. This is normal.
Big borders come when you set your resolution to 1024x768. Modes above 800x600, because they can't fit on TV, are sort of "crunched". First, we use a trick to skip every other line on the picture, similar to the trick used when there is no interlace support on the video chipset. So, instead of 768 displayed lines, the real value is 384. With interlace, this is halved to 192 lines per field. For a full frame with 288 standard lines, this means a big black border below and above the displayed picture. To squeeze all 1024 pixels horizontally, we double the dot clock normally used (28 instead of 14Mhz). This is equivalent of using a 512 pixel wide mode. If 640 pixel wide resolutions already have a small border, with 512 the border is even bigger. However, things begin to look better once you move up on resolutions. 1600x1200 already fills up the screen again.
Note that due to the high horizontal resolution of modes above 800x600, detail might be lost, since TVs have usually low bandwidth video support.

Regarding the TVs themselves, some modes can be used on a 16:9 TV. I personally have a Sony 28FX20 (FD Wega) and 320x200 modes(640x400) can be zoomed to full screen, since they have an almost exact aspect ratio as 16:9 (16:10). Its also possible to make compressed video modes. This would yield the best possible quality. However, 16:9 modes aren't common on PC land. 1024x576, for example, would be beautiful for this. If it existed... Contrary to what I previously said, VGATV won't produce a properly compressed video mode.
The image will be ok, of course, but I would have to know the aspect ratio is 16:9 or similar, and act accordingly. Instead of doubling the dot clock, I would have to multiply it by about 41%. 20Mhz dot clock for 1024 horizontal pixels, with a 1280 pixel wide frame (PAL timings, NTSC would be 20.16Mhz). This would require special clock programming, and some (many?) chipsets don't allow it.

Here are some PDF files from RGB to composite video chips you can use to base your own converter.

Remember to check for the evaluation boards on the above AD chips. I don't know if they come complete with a box or not, the PDF only mentions about the boards and it isn't said if the components come soldered or not. For the price they ask, it's better the thing comes with everything included...

Now you can get some schematics so you can build your converter more easily.