I think the poster was looking for vCalendar (now iCalendar), and to
my knowledge that hasn't been absorbed into the xml borg yet. The
representational power and syntax of vCard is very similar however,
so I'm sure the approach could be the same: parameters are mapped
to XML attributes, and structured values with positional components
(like a postal address) are given subelement names.
I'm not yet to the point where i can speed-read DTDs, so I'm not
sure how they are handling the vCard "type-grouping" capability,
nor what happens when the value is actually kept in a vCard "VALUE" parameter,
nor what they do with "<" or "&" in a vCard value or parameter.
There's also a proposed vCard 3 extension for better handling of
language; that should probably be mapped to some general xml facility (xml:lang?).
I suspect there are some white space issues in there too, but
I always get confused by white space discussions in XML, and this
is a weekend :).
-mda