Hmm...I noticed it today, its gone!
I know eGroups was acquired by Yahoo!, but I was able to browse the xml-cert group even after the acquisition. But when I searched today I was not able to find it.
There was some concern about 'real questions' being discussed in this group. Since it was an un-moderated discussion board, people didn't heed the warnings. So I'm guessing, may be they shut it down because of legal reasons.
Anyway, as my post reads, it wasn't a great group either. For beginners it provided ample information, but mostly redundant stuff. Don't worry, we can do a lot more here at Javaranch.
I can help you out if you have any questions about the certification. Just ask
Cheers!
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Ajith Kallambella M. Sun Certified Programmer for the Java�2 Platform.
IBM Certified Developer - XML and Related Technologies, V1.