Below are major communities for sharing audio under CC licenses. For other communities, see:
The Internet Archive is a digital library of internet sites and other cultural artifacts in digital form, including audio, moving images, texts, and archived web pages. See the Case Study for more information.
How to publish on Internet Archive
Archive.org implements the CC license chooser through the Partner Interface.
During the file upload process you are given this option:
Clicking either one of those options opens up a window to creativecommons.org in which you can select a CC license or dedicate your upload to the public domain using CC0.
How to use CC Publisher to add files >500MB
SoundCloud is a music and audio sharing community that allows artists to upload its works under the full suite of CC licenses. Its set of tools integrate nicely across the web, with adoptions from well known artists and labels.