The world has been divided into 6 DVD regions or zones, since Hollywood (basically) thought this would be a good way to control distribution at different times at different places. There is also a region 7 reserved for future use, and a region 8 reserved for international flights and other special use. Of course consumers are rarely happy with these kind of control, and of course this region encoding are so easy to hack that anyone with interest gets a region-free player. Even players from well-known brands kan be modified. Some studios introduced RCE or Region Coding Enhancement to make their customers even more pissed and download films from the net instead of buying them, where the DVD itself basically checks if the player is set to a region and not just set to accept "all regions". This is also called "region zero", but technically that doesn't exist. A "region free" DVD is simply set to region 1-6. Look below for a map of the various regions.
So how do you get rid of the regional encoding? On a computer it's fairly simple. Install dedicated software for the purpose and you'll never have to worry about them again. Another irritating thing about the DVD standard are UOP (User Operation Prohibitations). These programs will also disable that, making you able to press perform any action you want at any time (like fast-forwarding through the copyright-warnings) and remove the dreaded forced subtitles frequently used in Europe. For standalone players it can be more tricky, so be sure to check a site like dvdrhelp.com before you buy a player to be sure that it can be easily made region-free. Or even better – get it region free from the store! If you live in Norway, many shops will try to convince you that there is no need for a region-free player anymore since everything is released in Region 2. This is not true. First of all it's usually a lot cheaper to buy DVDs in other countries. Secondly, many special editions are rare films will never be released in Norway or even Europe at all.
In addition to the regional encoding, there is also another thing that sometimes makes it hard to watch a foreign DVD. There are three different TV colour systems, called NTSC, PAL and PAL SECAM. NTSC runs at 60Hz or 30fps and is used in USA, Japan and large parts of Asia. PAL runs at 50Hz or 25fps and is used in Europe, South-America, Africa, Russia and Australia. Most new PAL TVs support NTSC without any trouble, and so does the DVD-players sold in PAL countries. The other way there is more trouble unfortunaty, so if you live in a NTSC-country you'll have to get a PAL-compatible player.
There are basically two copy-protection systems involved with DVD, one digital and one analog.
The digital one protects the DVD from being copied digitally and is called CSS. Of course this was hacked after a software-player producer forgot to encrypt the source code for it. The controversial program was called DeCSS, and it caused quite a lot of attention here in Norway because one of the people behind it lived her, known as DVD-Jon. He claimed he made the program to be able to watch DVDs on Linux, and won in court, making it clear that it is not illegal to break the copy-protection systems the industry puts on to limit consumers rights even though it's completely legal to make digital copies of audio aswell as video for private use (in Norway). The distributors try to tell you otherwise, but don't listen to them – read the laws instead at lovdata.no.
Macrovision is the analog copy-protection system that basically disturbs the analog signals the VCR uses to determine whether the image is light or dark. This will probably make your VCR go crazy so you'll have to reset it by pulling out the cord. At least you won't be able to record anything from a MacroVision-protected source. But of course this causes problems. You might have noticed the Macrovision logo along with "Quality Protection" on some DVDs. This is certainly only meant for the film studio, because MacroVision actually degrades the picture quality. Again, there are no laws against – at least in Norway – copying a DVD to a VHS for private use. If you have a stand-alone player it's probably difficult to do something about this without changing the player physically. There might also be some codes you can input on your remote. There are also seperate MacroVision-removal-boxes. But I recommend that you get a (cheap) DVD player to your PC instead. This way it gets much easier (and also much more important since you can't plug the video cable into the VCR with macrovision enabled; you have to plug it directly into the TV, and this is not practical if you have only one SCART input (Europe) in your TV.