Creating an article
A short introduction in German for writing Wiki-articles can be found at Informationswissenschaftlern der Universität des Saarlandes. For more detailed descriptions please consult Wikipedia-Handbuch, in particular Bearbeiten and Textgestaltung or their english equivalents, Editing and Text formatting.
OpenOffice 2.3 has a MediaWiki export filter, so you can use OO Writer for formatting and then export that.
generating a box of source code (e.g. to cite a CORRECT.LP)
Simply introduce a blank at the start of a line. To avoid interruptions of the box, empty lines must start with a blank as well.