To make a long story short, XML-RPC packages up a procedure call as XML, sends it to a server using HTTP, and parses the response. It's mostly useful for gluing together distributed web applications, but it's also handy for cross-network scripting. There are XML-RPC implementations for Python, Perl, PHP, Zope, REBOL, LISP, Dylan, Visual Basic, and a bunch of other languages.
Thesis: Now that Christmas is over, it's time to start work on my thesis again. I've successfully modified the d2c compiler to build dispatch tables; now I just need to compress them and write about the whole experience. :-)