Don't worry, Nintendo's on YOUR SIDE:
Nintendo Online StoreYou can get a WiFi Dongle that connects to your PC or a LAN adapter that plugs into one of the USB ports. Also, the USB dongle for the DS is the same as the one for the Wii, so if you want the freedom of wireless or want to kill two birds with one stone I'd suggest the WiFi Dongle, or just getting a WiFi router, but there's also the LAN option.