multi-project builds

[Marc Dugger <md...@sunsetdirect.com>]

I want to define a "commons" project that contains only reusable
components and will be built and included in all my other application
projects.  However, I don't understand yet how to specify a sub-project
in the dependency section of the POM of an application project.  If, for
example, my project directory structure is like:
 
|--my project
|--master-project.xml
            |--commons
                        |--project.xml
                        |--src/
                        |--..etc.
            |--app1
                        |--project.xml
                        |--src/
                        
.should app1's project.xml contain a dependency for commons?  Do I need
to define a goal in app1's maven.xml to copy over the .jar produced from
commons's build?  Thanks in advance.