comScore released a API called comScore MyMetrix today; this suggests comScore data could be imported directly into Web Analytics Platforms:

"…Currently, the comScore MyMetrix API is available for integration with the following comScore services: Media Metrix, Local Markets, World Metrix, Plan Metrix, Ad Metrix, Video Metrix and Campaign Metrix. Other services, including qSearch 2.0, will be available in the near future. "

"..The comScore MyMetrix API can be accessed by any framework that supports connecting to SOAP-based web services, such as Microsoft.NET, Java, Perl, Python, etc. "

I'm not sure of all the steps involved to get comScore data into, say Omniture, Coremetrics or Google Analytics - though it would seem, that it would be a valuable overlay to traffic and visitor information already collected - especially if the pricing/licensing could be worked out in a way that's transparent.