Finding a WEP key.

Hello,

I'm trying to search for a WEP KEY of a wireless network which I haven't used yet. I want to crack the key by finding the software that finds the IP address and the WEP KEY for the available network. This network is not been installed on my system, I will use it after I can find the key.

Basic system config that required:
win XP
Intel P4
Wi-fi enabled
VPN compatible.

Regards,
Modi Zhalan.