There are a couple of ways to get to this data, including simply using the Keychain Access utility, but probably the easiest way to get to this specific data is to go through Airport System Preferences. Go into the Airport control area of Mac OS X and you’ll find a list of all the different networks you’ve successfully joined in the past, including those with and without passwords.
Open up System Preferences –> Network –> Airport –> Configure…:
Pick the network you need and click on the little “EDIT” button and a new window pops up with specific information on this network:
Click on the “Show Password” checkbox, and ….
The password is shown in hex but dont worry it’ll still work when you paste it into your new WIFI profile if you choose to create one.
