This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
I think you can summarize the difference pretty succinctly as UDDI being a specific enabling technology (which Web Services can make use of) and ebXML being a broad, strategic architecture for eBusiness interactions. I actually found a great ebXML overview book "ebXML: The New Global Standard for Doing Business on the Internet" (that you can occasional find at discount these days) if you wanted a quick read/overview. Paul Monday Author, Web Service Design Patterns: Java Edition
Paul B. Monday<br />Author, Web Service Patterns: Java Edition