DS games are not region locked, you can play a Japanese DS game on a US DSi.
DSi store access is allocated by region though, so some DSiware might not be available.
The DSi is not region-locked, it can play a Japanese game regardless of where the DSi came from.
Yes.
Yes, the Nintendo DSi can play regular US DS games, as they are not region locked. However there is a type of game marked as 'DSi-enhanced', which are region locked. A UK DSi cannot play a US copy of Pokemon Conquest, for example.
Yes you can unless if their DSi Enhanced the game only plays on the region the system is from.Other than that DS games aren't region locked making them playable on any DS, DS Lite, or DSi but I'm not sure about the 3DS.
Flipnote access you need flipnotes from japan to have a dsi with complete japan access you need a Japanese dsi.
A US DSi can play UK games
Yes. A European DSi XL will play most US region game cards for the DS. There are, however, certain games that are region locked because they are DSi exclusive or have DSi exclusive features. (Such as Pokémon Black and White) Also, as it is a US DSi XL, you will not be able to buy DSiWare from the European region.
Buy a japaneze game! I meant after you've bought a Japanese game what kind of freeload/software is there that lets you play imported-Japanese games?
No; because the newer Nintendo DS's unfortunately have a regional coding in place; so only games of the respective languages are compatible on that DSi.
Yes, DS games are not region-locked. Any console will play any games.
DSi Ware games and other downloadable content The Nintendo DSi Shop is specific to the region for which the system was manufactured. For example, a Japanese system can download DSi Ware games and other software only from the Nintendo DSi Shop for the Japanese region, regardless of where the system is being played. Nintendo DSi exclusive game cards Nintendo DSi game cards that are only compatible with Nintendo DSi and Nintendo DSi XL (and not Nintendo DS or Nintendo DS Lite) are region locked. This means game cards manufactured for the U.S. market would not work in a system made for another country. Nintendo DS / Nintendo DS Lite game cards Older Nintendo DS and DS Lite software is region-free, so you can play most of that software on a Nintendo DSi and Nintendo DSi XL from any region. It's possible, however, that future Nintendo DS software will incorporate region encoding. In these instances, these games would not work in a system made for another country. Source: http://www.nintendo.com/consumer/systems/dsi/en_na/faq.jsp#vers
I dont know if you could DOWNLOAD US ps3 games to a japanese ps3, but you CAN play US ps3 disk games on a japanese ps3.