I know what you are thinking...
Setting up WPA on an AP is so easy even my mom could do it!
Well, Cisco APs give you 1001 options and no clear way of setting up WPA-PSK.
To configure these devices here is what you need to do:
1) Express Security: Setup the SSID with Encryption of "None" and not WPA (yea I know...).
2) Under Security\Encryption Manager, select to use a Cipher and pick the option for TKIP.
3) Under Security\SSID Manager, select your SSID, and then pick "Open Authentication" with "No Addition". Then change Key Management to "Manditory" and select the "WPA" checkbox. Enter a WPA Pre-Shared Key.
I ignored the other billion options.