Creative Commons has opened a public comment period for the first draft of CC 4.0 licenses. Guidelines for license development include:

• Producing a 4.0 suite that addresses pressing challenges of important adopters, including those in countries where localized version of CC licenses have not existed, and never may, for any number of reasons;
• Maximizing interoperability, reducing license proliferation and promoting standardization where possible; and
• Longevity and ease of use.

You can see the first draft here: http://wiki.creativecommons.org/4.0/Draft_1, or visit the Creative Commons blog for more information: http://creativecommons.org/weblog/entry/32157