So You Want to Write a Book (about software)?
Advice from some people who know.
This installment of my series on writing about software is brief: O'Reilly has an excellent online publication called So You Want to Write a Book?, and it's full of good advice whether you plan to write a complete book or not. O'Reilly isn't the only publisher of computer books out there, but they're certainly one of the key ones, and this book offers excellent advice for preparing your content and for assembling all the necessary information if you want to move forward with publishing a complete book with them, with another publisher, or on your own. Even tech writers creating documentation for internal use at their company can learn something about book preparation from it.