Hi there,
I didn´t have to install anything from Microsoft paraticularly when I did WPA with LEAP. I was using the Dell LEAP and IBM LEAP clients. I only needed to upgrade them in order to get the WPA TKIP and LEAP mixed support.
However I think you might be able to get some updates from Microsoft if you like.
If using the Cisco Aironet Client manager. I suppose and update on that one would help to support WPA.
This is a good link (cco login required)
http://www.cisco.com/en/US/partner/products/hw/wireless/ps4570/products_configuration_example09186a00801c40b6.shtml
I have tested this myself and it has worked fine.
Hope this helps.