First you detect the network with Kismet.
Then you can crack WEP keys using Airsnort brought to you by the Shmoo group.

You can do it with either of these tools alone, but it helps to use them together.

Then with the help of ettercap you can wreak general havoc on the network. This includes man in the middle attacks, Denial Of Service, full sniffing of ssl traffic, full sniffing of SWITCHED networks (not really important in an 802.11 network) and all the other goodies that the evil bastads that created it have put into it.

Thus with these three tools (and Ethereal if you want even more fun) you may also have a laptop aptly named "eris" just like me. And this should anwser the second question of "How did I get hacked?"
I hope you learned something that a five second google search would have taught you.