Please Answer I Need Help Connecting To Wifi?

Ok well I have a Cisco Linsky E3000 router, and I am trying to access WiFi on my Nintendo DS Lite, but I get an error message EVERY TIME. Anyway I know that my router is WAP and my DS is WEP but I have guest access with NO security enabled on my router. Shouldn't I be able to use that to access my WiFi? Please help. I really need to trade pokemon, lol. Im not to smart when it comes to routers. Any help is greatly appreciated.