Well, "Better Builds with Maven" is finally out there.

http://library.mergere.com/

The book is the first about Maven 2, and was written by Maven developers myself, Jason van Zyl, John Casey, Vincent Massol, and Carlos Sanchez. The chapters include:

• An introduction to Maven 2.0
• Creating, compiling and packaging your first project
• Best practices and real-world examples
• Building J2EE Applications
• Extending builds by creating your own Maven plugins
• Monitoring the health of source code, testing, dependencies and releases
• Team collaboration and utilising Continuum for continuous integration
• Converting existing Ant builds to Maven

If you happened to get the pre-release before today, the book has been updated - you can download it again from the website.