The main CC licenses have been released in three versions: 1.0, 2.0 and 2.5. References to changes associated with each version will follow.
Initial version, released 2002-12-16.
Released 2004-05-25. Changes explained at http://creativecommons.org/weblog/entry/4216
In development. See http://lists.ibiblio.org/pipermail/cc-licenses/2006-August/003855.html for current drafts and explanation.