The Open Media Streaming Project has added CC metadata support to their streaming audio server and player.

OMSP’s NeMeSi player displaying license info for a stream.

They say:

Please note that the CC stuff in the source code is in very alpha stage: no more than IETF’s-style “running code” to test a soon-to-be-released specification proposal for streaming Creative Commons licensing meta-data over RTSP/RTP protocols.