I have an old laptop that I always take with me on trips. I finally decided to get a new one – it was just getting too slow.
Last weekend I was going to my brother’s place up north. The problem was, he was out of town and I really wanted to use his wireless when I got there.
So instead of bothering him for the key, I was able to pull the old wireless keys from that clunky old laptop.
I did it using a free tool from http://www.nirsoft.net called WirelessKeyView:

It is a simple tool that will scan the registry for all the wireless networks you have ever joined, and show you a list of passwords.
It can pull WPA, WEP keys, and will even show you both the password and the hex key for the password.
The latest version can be found here:
http://www.nirsoft.net/utils/wireless_key.html
Best of all it is free for commercial and personal use.
