Il y aussi cette page, qui explique comment transférer ses infos vers une nouvelle DS (Lite par exemple) :
http://www.nintendo.com/consumer/systems/dslite/faq.jsp#transfer
Can I transfer my Nintendo Wi-Fi ID to another Nintendo DS or DS Lite?
You have the ability to transfer your Nintendo Wi-Fi Connection ID to another Nintendo DS. This is usefull if you have purchased another Nitendo DS system (such as those who want to purchase the newer Nintendo DS Lite), and means you won´t have to worry about getting new Friend Codes or losing your Wi-Fi Connection stats.
Click "here"
(http://www.nintendowifi.com/consumerservice/showT
opic.do?topicId=GTS_Online_Activity&catId=GTS_Onli
ne_Misc?locale=en_US#Online_NWFCID_transfer) to go to NintendoWiFi.com´s step-by-step instructions on transfering a Nintendo Wi-Fi Connection ID to another Nintendo DS or DS Lite.