Sorry I forgot to answer your query in my last mail. Yes, XML Certification is harder than SCJP, but not very much. Passing is equally tough (or easy ;-)) in both the exams but when it comes to scoring I would say XML is harder, I haven't heard the kind of scores we hear for SCJP. Well for books and resources please refer to the links I gave in the starting of this thread, one very useful link is http://www.whizlabs.com/products/xmlwhiz/ibm-xml-faq.html
As far as SCWCD and XML are concerned, I believe you should first go for SCWCD, I have heard that it has more respect than XML certification. Please don't think that I am demeaning XML certification. I am myself SCJP and XML but not SCWCD. But my current view is that SCWCD has more respect than XML as Sun is promoting it much better than IBM is promoting XML. Lots of people know about SCWCD but a very few care about XML certification. Though in the long run XML will emerge as THE technology but currently I would suggest that first go for SCWCD and then XML.
Hope it helps. Please let me know if there is anything else I can do to help.
You are always welcome! I am always there for you, just let me know.