Multi Player Games
What hardware do you need to play multi-player games on a DS Lite or DSi? And can a DS Lite and DSi sync together to play multi-player games??
The DS, DS Lite and DSi all come fully equipped for multi-player game play. No special cables or other equipment is needed.
In fact, in many cases you only need one game cartridge to play on multiple systems all at the same time. The DSi may be compatible with some newer games that the older DS and DS Lite may not be able to play (though I am not aware of any such games as of now), in which case multi-player functions would require another DSi rather than a DS Lite. These games (DSi ONLY games) should be properly marked and confusion should be easy to avoid.
Here's how multi-player on the DS works: (this only applies to DS games - the DS and DS Lite can both play Game Boy Advance games, but these are limited to single player mode only)
When you purchase a game, the box will have multi-player information on the back. Some games are single player only, others can be played by only two at a time, and others can be played by up to eight people at a time.
There are several different modes of multi-player play.
On some games only one DS game system and cartridge is needed. Players take turns and pass the DS back and forth.
Other games use the wireless capabilities of the DS to link up and play together within 30 feet of each other, or even over the Internet. Again, on the back of the game box you will see "Multi-Card Play" or "Single-Card DS Download Play" or "Nintendo Wi-Fi Connection".
Multi-Card Play requires that each player owns his own copy of the game they would like to play. They both start the game, then in the game under the multi-player options they can connect and play together. Some games allow more than two systems to connect at a time. Again, the multi-player connection is achieved by use of the Wi-Fi card that is already inside the DS (the same kind of Wi-Fi card most laptops and computers use today).
Single-Card DS Download Play is exactly the same as the Multi-Card Play except that only one card is needed. The player who has the game in their DS starts the game, then (if the game is capable of DS Download Play - check the back of the box) they select the option to play with other players who do not have the cartridge. At this point, the other DS players turn on their system and select DS Download Play from the main menu. Their DS will then look for the broadcast signal from the system with the game in it, and download just enough information to play the game in multi-player mode.
DS Download Play can do more than just multi-player DS games. Some Nintendo Wii games can download information to the DS for various purposes, and a Wii that can access the Internet through the Nintendo Channel can even download trial games for the DS using this Download Play option.
Finally, some games can connect players from around the world using the Nintendo Wi-Fi Connection. The DS can connect to the Internet using any wireless router. Unfortunately, the DS is not compatible with WPA encryption, so if the wireless access point has a password, it must be using WEP encryption (an older, less secure standard for securing wireless connections). If the wireless access point is not secured, the DS should be able to connect without any trouble.
If your wireless router uses WPA encryption and your DS cannot connect, Nintendo makes a Wi-Fi USB Adapter that plugs into your computer and broadcasts a signal that works with your DS. I believe it costs about $50 (unfortunately, I couldn't find it on the Best Buy website) and it works with the Wii as well (though the Wii is compatible with WPA, so this wouldn't be an issue for a Wii owner).
Some games are even compatible with all of these types of multi-player modes. You just have to check the back of the box (or the product description on the vendor's site).
One final note for you since it seems you may have a situation where one individual will have a brand new DSi and the other will have an older DS Lite. They each have their advantages and problems, so not everyone wants a DSi and some people are trading their DS Lites in for DSi's. The DS Lite comes pre-installed with one (somewhat) fun multi-player application that any DS user can play wirelessly with other DS users. The DSi also has this application (called Pictochat), but the DSi comes with many new pre-installed applications that the DS is not compatible with (including the ability to play songs from an SD card, take pictures and manipulate them with its cameras, and many other fun new things).
If I were a young child with a DS Lite and my brother/sister/friend got a brand new DSi with all of these cool new features, I would be a little sad. The only thing the DS Lite can do that the DSi cannot do is play old Game Boy Advance games (which is very important to some users, and others don't care at all). Some retailers are taking DS Lites in as a trade-in for the new DSi (you pay something like eighty or seventy dollars, trade in the older DS and get a DSi). If the DS Lite owner in your life becomes jealous of the new DSi you may want to consider this as an option, though there is a limited time on the offer.