How to Set Up An Internet Connection

I've searched the internet fruitlessly trying to find an answer to
what should be a simple question, given that this is probably one of
the most common things that people do with a computer.

I have

1. A new laptop running Vissta
2. A DSL connection to a 2wire 2700 modem/router
3. A desktop hardwied to the modem router.

I want have a wireless connection to the laptop. I gave

1. Run through connect to the internet dialog and see a connection to
"2WIRE387."
2. Click it and the it asks for a "secuirity key or passphrase."

I have no idea what it wants and there is no explanation anywhere. I
would appreciate information.