[kubuntu] Turn my laptop into a router?

view story

http://ubuntuforums.org – My home router uses WPA2 for my Wi-Fi, but I'm experimenting with homebrew programs on my Nintendo DS and it requires an internet connection. However, the DS's current firmware (and even all the custom homebrew firmware I could find) only supports the WEP protocol. I do not want to downgrade my router from WPA2 to WEP however. So is there a way for me to turn my laptop into a Wi-Fi hotspot serving WEP, while being itself connected via WPA2? I want it to be able to connect to my WPA2 router, but transmit WEP to my DS, preferably with a different passkey for security (I was able to crack a W (Hardware)