From the Free Software Foundation's licence recommendations:
The full text is here: http://www.gnu.org/licenses/license-...endations.html. Oddly, it doesn't mention the BSD licence, speaking only of Apache Licence 2.0.When you contribute to an existing project, you should usually release your modified versions under the same license as the original work. It's good to cooperate with the project's maintainers, and using a different license for your modifications often makes that cooperation very difficult. You should only do that when there is a strong reason to justify it.