Fedora are switching their documentation to the Creative Commons BY-SA license. What's interesting about this change is the way they are doing it: According to their wiki, they are invoking the following clause from their Contributor's License Agreement:
... a perpetual, non-exclusive, worldwide, fully paid-up, royalty free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute your Contribution and such derivative works;
By contrast, we're still mired in an ambigiuous copyright situation with the Debian wiki. Franklin Piat posted a proposal for resolving the mess back in June. One technique suggested in the proposal is for a condition of future contribution being agreeing to relicense existing contributions.