>How?

If you use Intel ProSet (comes with all centrino enabled computers), just right click on the icon and "disable radio." When you need to enable wireless again just right-click and choose enable.

There's no need to disable the wired adapter because when you are unplugged it is not in use.

If you don't have Intel ProSet, you just check the option for the network adaptor to show an icon in the system tray and you can disable by right-clicking that icon.