Start with the guide on Vista:
www.uio.no/english/services/it/network/student-residential-network/instructions/vista/index.html
At the point where you choose 'Local area connection' you should choose
'Wireless network connection' and get something like this:
Disable IPv6 by unchecking the box.
Then choose the Sharing/Deling tab:
Uncheck the box on the top. (Allow other computers...)
Then click OK button and close the 'Network and sharing' window.