There are a couple of sites out there that if you have ever been interested in XML you have probaby come across. There is xml.com which is part of the O'Reilly Network that has broad coverage with a very hands on approach to understanding the technology. There is also xml.org that also has a broad view but tends to break things down by industry areas and is more XML standards news oriented. Today I found out about xml.gov from an interesting article at Government Computing News. What you will find there are standards and practices for using XML in the US Federal Government. while the XML Developers Guide (pdf) there is from 2002 much of the advice is very sage and is worth checking out. I think it is particularly interesting in how it goes about laying down policies for use of XML within the government including versioning. As an example of a policy that may be a bit stonger than what I would recommend but is certainly admirable (especially for the prominence given to the W3C😞"Standards promulgated by nationally or internationally accredited standards bodies (such as ISO, IEEE, ANSI, UN/CEFACT, etc.) MUST be adhered to when developing applications within the domain that the standard addresses. The only exception to this rule is when a standard produced by one of these bodies competes with a similar product of the W3C. In this case, only, the W3C has precedence.In general, production applications SHOULD only use software that implements W3C Final Recommendations and final specifications of the accredited standards bodies referenced in the above paragraph."
If you are interested in schema I would also recommend checking out the EPA Schema Design Rules (pdf). I think it goes into a bit more depth than the guide above on this topic.
I've only had a chance to glance at both of these but they are getting added to my reading list and I'm sure I'll have more to say if not on the guides themselves then on ideas that come from their content.
