Techworld is reporting that Microsoft has released an update which adds support for WPA2 to Windows XP:
May 04, 2005 The Wi-Fi Protected Access 2 (WPA2)/Wireless Provisioning Services Information Element (WPS IE) Update for computers that are running Microsoft Windows XP with Service Pack 2 (SP2) is available.This update enhances the Windows XP wireless client software with support for the new Wi-Fi Alliance certification for wireless security. Configuring WPA2 for Windows XP Requirements for wireless using WPA2 on Windows XP with Service Pack 2 Your wireless card must support 802.1x, AES, and WPA2.
Microsoft has released native support for the IEEE 802.11i wireless security specification in Windows XP and its variants, nearly a year after the standard's ratification. The update, made available on Friday, gives Windows compatibility with WPA2 - the certification based on 802.11i - as well as a standard designed to help laptops connect to secure public hotspots.
The update isn't available through Windows Update but can be found on Microsoft's site here:
Update for Windows XP (KB893357)(requires 'Genuine Microsoft' authentication)
The accompanying knowledgebase article mentions the following:
You must use the WPA2/WPS IE Update together with the following:
• Wireless access points that support WPA2. • Wireless network adaptors that support WPA2. • Windows XP wireless network adaptor drivers that support the passing of WPA2 capabilities to Windows Wireless Auto Configuration.
The WPA2/WPS IE Update modifies the following dialog boxes:
• When you are connected to a WPA2 capable wireless network, the type of network is displayed as WPA2 in the Choose A Wireless Network dialog box. • On the Association tab for the properties of a wireless network, the Network Authentication list has the following additional options:
WPA2-PSK - for WPA2 Personal
Note These options are not present if the wireless network adaptor driver does not support WPA2.
So it sounds like you won't see any of the updated dialogs without WPA2 compatible drivers for your NIC and that enabling WPA2 security will require a compatible WAP and NIC.
You can find some further details on this update and WPA2 in this month's Microsoft 'The Cable Guy' column, 'Wi-Fi Protected Access 2 (WPA2) Overview'.