Yes it's true that you can make the xbox multi region. There is a disk called regionX which allows you to do it, amazon have it for £17.99
http://www.amazon.co.uk/exec/obidos/ASIN/B000063S36/ref=sr_aps_videogames_1_1/026-8412692-2902866
MOST Xboxes will recognise MOST DVD-R/Ws and DVD+R/Ws, this really comes down to the type of DVD drive that is in the xbox, some people have really good ones which will read anything, others have naff ones which won't. There's no way of telling other than buying an xbox and having a go, no particular date or place of manufacture is better than another, it's just pot luck.
The price of the regionX disk is a little steep if you ask me, you'd be better buying an xbox with a modchip installed
www.baldbouncer.co.uk these allow you to run "backed-up" games as well as home written prgrams such DVDX 2, this is a dvd player that doesn't need the offical MS infra red dongle to play dvds. They are also effectively region free machines once they are chipped. The cost of a pre-modified Xbox is £220, the official dvd play back kit and the regionx disk are nearly £40 together.
[Illegal suggestion moderated]
One last point, if you have now, or will in the future have a TV/plasma/projector that can take component inputs then the xbox can output a component video signal, too. In fact it can do better than that, it can output a progressive scan component signal, from games and dvds.
Worth thinking about.
HTH
Owain