[Alvin.C]

WirelessKeyView by NirSoft is a free, standalone executable program written for Windows XP, which can recover WEP and WPA wireless network keys stored in the 'Wireless Zero Configuration' service of Windows XP. You can then export the keys to a text document.

You can download it for free here: WirelessKeyView: Recover lost WEP/WPA key stored by Wireless Zero Configuration service

This is a handy utility to use if you've forgotten a WEP / WPA key for a protected network you've connected to using Windows XP Wireless Zero Configuration.