From The Evanescence Reference
You can export the text and editing history of a particular page or set of pages wrapped in some XML. This can be imported into another wiki using MediaWiki via the import page.
To export pages, enter the titles in the text box below, one title per line, and select whether you want the current revision as well as all old revisions, with the page history lines, or the current revision with the info about the last edit.
In the latter case you can also use a link, for example Special:Export/Main Page for the page "Main Page".