One of the facets of web services that has always seemed like "the emporer's new clothes" to me is UDDI. I've never understood how I'd use it in real life (at least until such time that there are significant web services that function as commodities). Tarak Modi, in a recent article on the difference between UDDI and WSIL says:
Let's say that your company needs to wire significant amounts of money from one place to another on a regular basis and you wanted to automate this process by utilizing a readily available Web Service. To do so, assume that you did a search in a UDDI registry and three such services showed up. Based on the discussion above, two of the three entries will probably be invalid. The next question is, do you even know or trust the vendor that is publishing the third entry? How can you be sure that this is a legitimate company? Even if you know and trust the vendor, you will probably not be able to or even want to use the service without entering into a Service Level Agreement (SLA) with the vendor.
WSIL is an alternative (and perhaps compliment) to UDDI that allows web service vendors to advertise the offer on their own site. The standard insists that the WSIL document be placed in a file called inspection.wsil in the web root of the site. After that, it would be a simple matter for Google to pick these up and categorize them . Viola, instant web services directory.
Seems like the way to go to me.