Well bam, you think i dont know? Ill prove you wrong
There are three methods :
1. PassMe
2. FlashMe
3. WifiMe
Each one has his advantages and limits.
1. the 'PassMe' method : It's a card (called 'PassMe' or sometimes 'MagicKey') placed between the nds and an original nds game. In this case, the NDS boots on a flash cart where there is Linux.
For more info to use this method :
http://www.dslinux.org/index.php?showtopic=430
2. the 'WifiMe' method : You need a Wifi card. You have to install specific drivers for your card. After that, start the ds and choose 'DS Download Play'. The DS will download a virtual PasseMe from the computer, which allow the nds to load DSLinux from the FlashCart. At every boot, you need to use your computer to load DSLinux. Note that you need a really specific card and the driver exists only for Windows2000 or XP.
For more info to use this method :
http://www.aaronrogers.com/nintendods/wifime.php
3. the 'FlashMe' method : You need (a PassMe OR a Wifi card : one time) AND a gbamp (every time). This method change the firmware (a basic operating system into the nds) of the DS. After that, the DS allow you to choose to see a demo on the gbamp. The demo will be DSLinux so the DS will load it.
* with a PassMe : Start the DS with the PassMe to flash the firmware. After doing it, you'll never need the PassMe. At each boot, the console will ask you if you want boot DSLinux or the standard Nintendo OS.
For more info to use this method :
http://ds.gcdev.com/dsfirmware/
* with the wificard : You have to use the WifiMe method to flash the firmware as with the PassMe. After that, it's like doing the 'FlashMe' method with a PassMe.