The video format of UK DVD's is 'PAL' (625 lines/frame at 50Hz on the TV set) and it is set for region 2 encoding. This is compared to North America where it is region 1 and the TV standard is NTSC (525 lines/frame at 60Hz.) If you try playing a PAL DVD on an NTSC TV, you'll lose color.
DVD's are encoded by region. North American DVD's are region 1. UK DVD's are region 2. DVD players in North America are designed to play only region 1 DVD's. If you try to play DVD's from other regions, you'll get an error.
Macrovision is a copy protection scheme meant to keep people from copying DVD's to video tapes. It makes the picture's brightness fade in and out, maybe even breaking up the picture completely. It's flawed because many old TV sets don't have the modern connections that DVD players have, but VCR's do have them. So, the only way to connect a DVD player to an old TV set is through the VCR. A good DVD player will have Macrovision disabled so that it'll be VCR friendly. You'll find that this is a rare feature.
There are four options to playing UK DVD's on American systems, from cheapest to most expensive: buy a codefree DVD player with a built-in PAL-to-NTSC converter, buy a DVD-ROM drive for your computer, buy a codefree DVD player, and modify an Xbox.
You can find a few code-free players on Amazon.com.
I recommend Philips DVP 3560K Multi-Region Multi Zone Region Free / Codefree 1080p UpConverting DVD Player with Karaoke, HDMI, USB & Multimedia DivX. Plays PAL / NTSC DVDs from Any Country - Remote & Karaoke
My friend bought a codefree DVD player. It arrived in a timely fashion and works straight out of the box. It was great to plug it in to her VCR inputs, pop in The League of Gentlemen (region 2 British Comedy) and have it work right out of the box! It responded faster than my high-end Panasonic H1000 progressive scan DVD player, which just makes me jealous.
The top 4 recommended code-free DVD drives are: Pioneer 103S IDE (slot in), Hitachi GD-2500, Toshiba SDM-1212, and Samsung SDR-606B. Most are 6x which is more than enough to play DVD in all its splendour; all the 10x DVD players coming out, as with all DVD players that will be produced in North America starting January 1, 2000, will and must have region-coding hardcoded into the player.
Here's a link with tips for region-free DVD-ROM drives.
I don't think it's much fun to watch movies at the computer, so I borrowed a device, an Avermedia Averkey 300, that changes a computer's VGA signal to NTSC so I can watch the DVD's on my TV.
Also, something I'd like to try someday is using a VGA to progressive-scan converter to watch DVD's from the computer on my TV at full resolution. But now we're getting into the reasons why this option is more expensive. The following devices will let you watch computer images on your high-end video equipment.
If your TV can handle 50Hz, you need a simple convertor for color signal NTSC/PAL. If not, as is the case for almost all TVs sold in North America, you need a digital convertor, around which converts color and Hz to NTSC. With a good converter and good quality DVD, the quality loss in the conversion should be minimal.
You may need a step-up transformer to convert American 110 Volt/60 Hz power to European 220 Volt/50 Hz Power for a DVD player you buy outside North America. Check this link for more
An Xbox is Microsoft's video game system.
Modifying an Xbox is the trickiest thing to do because you need skill with a soldering iron, and you need to surf the web for the software. If this doesn't scare you away, I would recommend buying an Xbox, and a SmartXX (or some other) mod chip kit. Note that you can find pricey pre-modded Xboxes on the Net. Then Download Slayer's EvoX Auto Installer.
This turned out to be my favorite way to go, because I ended up with one unit to play multi-region DVD's, play games, play game emulators, and play different movie files and music files. Connected to the Net, I even get movie trailers, Shoutcast radio stations and current weather information.
Your best bet for more information is the Xbox Scene website.