Music packages must be uploaded in a special way to be recognized by the add-on uploader.
Creating the Package
(Note: Not yet implemented) You must create a package containing exactly one .ogg file, one License.txt file, and one music.xml file. All other files will be removed from the package. Other audio formats are not supported.
You add-on will appear in the list of add-ons after it has been approved by a moderator.
To upload source files, do the same as you would for any other add-on. If you get a message saying some files were removed from the uploaded archive, please file a bug report, so that the necessary file-types can be added to the whitelist.