Follow these steps:
1. Go here - Request a Project and follow the steps - http://www.java.net/request_project.csp
2. A community leader will see this request and if necessary, "re-parent" your new project appropriately to be part of the parent JUG project on java.net.
3. Drop a mail to the JUG leaders mailing list with the name of your project, so an Oracle representative can make it public.
Detailed information about community objectives and projects on java.net can be found here: http://www.java.net/jugs/community-objectives