Interested in learning more about Maven? Start with my article Building Web Applications with Maven 2 (2007). The code is listed below as maven2example.zip.
Not sure where to find the information about a dependency? Try MvnRepository first. If you are still stumped, try jarFinder, jarhoo, JarIndex, or Google Code Search.
In July 2009 I gave a presentation on Maven at the Seattle Java Users Group (SeaJUG). You can download the slides below. You may also want to look at the sample Maven project with additional reporting (such as Cobertura coverage) turned on.