As has been posted here before, CC is working on version 4.0 of their licenses--in case you haven't seen it, the public draft is up in several different formats at http://wiki.creativecommons.org/4.0_Drafts
Right now their focus is on attribution, and they are asking several specific questions about things to change in the new version. (A few of the open questions: Is there too much flexibility in "reasonable manner"? Or not enough? Is there any information people should be required to provide that they aren't providing? Should you be able to use a shortcut by just providing a link, and if so, what should you have to include?)
The questions and space for comment is on the CC wiki here:
http://wiki.creativecommons.org/4.0/Attribution_and_marking#Questions_about_...
(Ultimately, we hope to be able to use the 4.0 license version as the default license version for Wikimedia projects--either BY-SA or BY, depending on which project you are using. Several Wikimedians are already participating in these discussions, as well as the legal staff and myself, but your input on things that have and haven't worked well in 3.0 would really help the process, especially if you have good examples.)
I will be posting this message around to some of the wikis as well, but please pass this message around where it is relevant, especially if you are active on non-English projects!
Cheers, Kat
wikimedia-l@lists.wikimedia.org