For the "edit" at the top of the page, assuming you're running 1.5, go to your wiki, and open "MediaWiki:Edit". Change it from "Edit" to "Modify" (or whatever you want to call it). For the edit in section headers, change "MediaWiki:Qbedit". No idea what "MediaWiki:editsection" changes, but you should probably change it too. I just found these by trial and error, but does anyone know if they are documented anywhere? All the best, Nick.