We (the Apache jUDDI project) are working on porting our code to work within the .NET framework. Specifically via WCF behaviors, so that's in the works.

To more directly answer your question, you'll need a UDDI server, credentials to the server, and permission to publish (ask the UDDI admin).

You'll need to create (or append) to the following UDDI structure:

Business > Service > Binding Template (which is your instance of service X (remember services are interface definitions).