Apple TV works fine with non-HDTV
A big problem people have with the Apple TV is that you ‘require an HDTV’ to use it with; and a lot of the reviews posted are repeating this statement.
We have had a couple of people write in asking if some combination of cables could be used to rectify this. We are here to report, there is nothing to rectify, all you need is a TV with component inputs. Several of the first photos and videos on the net showed a “480i”, which is standard ‘old TV’ resolution in the Apple TV settings menu.
To confirm, the people over at Rogue Amoeba Software hooked an Apple TV up to a ’square’ TV, and have a photo of it working just fine:

Friday 23 Mar 2007 | | Del.icio.us | News, Hardware Hacks

December 9th, 2007 at 7:55 pm
Also I have an old Sony 4:3 TV but according to this page: http://wiki.awkwardtv.org/wiki/Composite you can connect your TV using the green connector, run the patches and you get color output on your SD TV, using normal cables and withouth the need of costly converters.
December 6th, 2007 at 3:51 am
Okies guys i need your help in getting this straight,
I’m hopeless with technology so im hoping im reading this right.
So the apple tv will play on any older non HD TV? if so is it easy to do and what extra cables software do i need, if any? i think i just have the standard yellow, red and white ports, is that all i need or is there something else i need.
cheers and thanks for your help.