I just filed https://issues.apache.org/jira/browse/INFRA-3371 to get the wiki set up.
Once this is done it should be straightforward to (manually) migrate https://github.com/mesos/mesos/wiki/_pages there. It might be worth looking at http://incubator.apache.org/guides/website.html to start thinking about how to migrate the website. Cheers, Tom
