The Jellyfish Book
Together with Simon St.Laurent and Joe Johnston, Edd Dumbill wrote a
book on XML-RPC for O'Reilly and Associates on XML-RPC. It features a
rather fetching jellyfish on the cover.
Complete details of the book are available from
O'Reilly's web site.
Edd is responsible for the chapter on PHP, which includes a worked
example of creating a forum server, and hooking it up the O'Reilly's
in order to allow commenting on news stories from around the Web.
If you've benefitted from the effort he has put into writing this
software, then please consider buying the book!