I think several questions are doing to be found that are more appropriate to the wiki concept than a definitive question/answer concept. Are the options for marking something as wiki not available during beta?
Community wiki questions are a moderator-only feature. Anyone can make a community wiki answer, however.
Keep in mind that you might not really need community wiki at all. It shines when answers require collaborative editing, but with suggested edits in place even that is possible without CW.
I don't know which questions you had in mind as CW candidates when you asked this, but check out this blog post about community wiki, its uses, and its purpose.