So if you need to connect A PC to an Airport wireless network, you need to
- connect to the Airport base station using “Airport Admin Utility” (in the /Applications/Utilities folder on a Mac, or download the Airport Admin Utility for Windows v3.2)
- select the base station and click the “Configure” icon. Enter the base station password (or provide your Keychain password).
- From the “Base Station” menu, select “Equivalent Network Password…”
- The hexadecimal version of the network password is displayed, ready to be entered into the PC.
Apple’s documentation on this procedure is here.