OpenOffice.org XML Essentials
You should read this book if you want to extract data from an OpenOffice.org document, convert your data to an OpenOffice.org document, or simply find out how OpenOffice.org stores its data “under the hood.” Before we can talk about OpenOffice.org, we have to look at the current state of proprietary office suites and applications. In this world, all your documents are stored in a proprietary (often binary) format. As long as you stay within the office suite, this is not a problem. You can transfer data from one part of the suite to another; you can transfer text from the word processor to a presentation, or you can grab a set of numbers from the spreadsheet and convert it to a table in your word processing document.