As Tim says, when Adam writes, you really want to read it.

Here's an overview of XML-RPC, SOAP and REST based on a little bit of research.

XML-RPC is RPC over XML. It's simple.
SOAP is simple, but is the foundation for all the Webservice stuff (now there's a phrase).
REST is even simpler, back to basics, using http things like GET and PUT and URIs.

Tim dares to speak out. Is there an alternative?

XML enters the dusty world of finance. I know there's XBRL but that's complicated.

ZapThink :: Intelligence, Research, Analysis, and Insight on XML, Web Services and Service-Oriented Architectures

Stuff about browser based applications and forms and the future.
http://www.whatwg.org/
http://www.adambosworth.net/
http://bitworking.org/news/3270_Redux
http://www.infoworld.com/article/04/06/11/24OPstrategic_1.html

Another thought on Postcodes and Addresses. The reason the phone book doesn't contain postcodes (as you would think it would be in the best interests of the Post Office) is because BT and the Post Office couldn't agree a price. Even more reason to take away ownership from them.