robotsdobetter - 5:15 pm on Dec 13, 2005 (gmt 0)

Are Wikis hard to set up on an existing website? (Meaning lots of server-side work to get them up and running)

No, very easy, provided that you know the basics of PHP.

Are busy Wikis a nightmare to keep up with? Since anyone can pretty much edit on site documents, it seems there would be a lot of comments and edits that would need to be reversed, research for validity, or corrected on a daily basis.

This depends on whether you a few members that will help you out, but if you don't you can bet it will be a nightmare. You could require membership before people could edit, this would at least cut it down a bit.

What are the best uses for a Wiki?

MediaWiki seems to be the best, but haven't used them all, so maybe someone else can help you here?