Maven has a nice section to describe the license the artifact is released under. For instance:
<name>The Apache Software License, Version 2.0</name>
This was copied from Cargo: http://jira.codehaus.org/browse/CARGO-835
This is useful to projects that use license-checking tools to validate that dependencies are licensed in a manner acceptable to the project.
This is also useful for generating license reports for a project.