WPA involves two basic element:
encryption and access.
802.1x is the access component and that requires the use of a piece of client software known as a supplicant. The supplicant handles the authentication with the access point or RADIUS server to ensure that only someone with the correct credentials gets onto the wireless.
In WindowsXP, the supplicant is provided as part of (I think) SP1. There are also third-party supplicants by Meetinghouse and Funk for earlier Windows versions as well as XP.
Back to your situation. You need a supplicant in order to interact with the access point using the pre-shared key before you can "open the gate." http://hostap.epitest.fi/wpa_supplicant/
should do it.