Microsoft, along with IBM and SAP, announced they will close down their respective nodes in the public UDDI Business Registry, also known in our AHI as the UBR. [AHI = acronym-happy industry]  Microsoft's UBR is here, IBM's, etc).   The companies published a collective FAQ on the move.  

In short, seems to me this is a tragedy of the commons type of story.  All of the various implementations of UDDI worked together within the UBR, so interop was clearly demonstrated. (At this point, interop between UDDI registries is a real yawner, but 4 years ago, it was still a concept, a vision.  Things change quickly. )  But, there was no quality enforcement or governance on the UBR, because there was no direct funding.  Anyone could publish.  No one was checking quality or doing garbage collection.  So there was lots of, um, low-quality data in the UBR.  But, that phenomenon doesn't mean UDDI itself is low value, or is being discontinued.  

The vendors will continue support of UDDI, the protocol, in products and services.  For example, Microsoft includes UDDI Services in Windows Server 2003, and IBM includes a UDDI Version 3 registry in the "WebSphere Application Server v6 Network Deployment" bundle (the one that costs $15,000/cpu).   Visual Studio will continue to support UDDI. 

Companies will continue to use UDDI for internal registries.  I expect that there will be public UDDI registries, also, but probably not a "commons" arrangement.  Instead third parties will host for-fee service and will guarantee quality of the listings.  Just a guess.

CBDI Forum also commented on this move.