It depends on what you have. We will only let bugfixes into the BRANCH-1-8 now and all new features should go into HEAD. This weekend will see HEAD become BRANCH-1-9 as 1.9 enters RC1 and becomes bugfix only as well. HEAD will become 1.10 for new features.
You will need to get added to the developers area on the SourceForge project page. As both 1.8 and 1.9 are entering bugfix only, you will probably want to join us on IRC to discuss what you have and its possible impacts on the stability/release process, or you can just list them here and come back and check later