This is not the first time that the NSA has helped Microsoft (and other vendors by the way), they "reportedly" helped MS back in 1999. What the NSA
did was to contribute to the cryptography (security) of the operating system.
Here is a news link for more information Windows VISTA and the NSA
The reason that this is getting such airtime is because of the recent eavesdropping scandal where the NSA has been listening in on overseas calls etc.
That is fairly easy to check.
Install VISTA on to a system that has it's own internal network. Put a sniffer on it (like SNORT) and see if there are any suspicious traffic
eminating from the system.