] Micah takes you through the basics, shows you where
] XForms fits with other W3C standards, and gets you
] started with authoring. Once you're feeling a bit more
] confident this book serves as an excellent reference,
] with enough examples for you to copy and try out for
] yourself. The great thing about this book is that there
] isn't too much of it. It gives a good grounding in the
] subject without any waffle.

The full text of the book is available in HTML. Good timing. I've been meaning to learn XForms.

Push Button Paradise in Print: O'Reilly XForms Essentials