Wi-Fi DS Trouble

Hello.
I have a DS and am trying to set up its wifi. I have learned about the WEP and am able to change its settings to shared, which allows me to connect with the DS, but ruins the internet for the computers. I change it back to open and the computers' internet works again, but the DS's doesn't. How do I setup up computers to work with shared WEP and will changing the WEP to shared also mess up my Wii because it works with open, but I didn't test it with shared.

Pnuewm