is a WikiBookmarklet, that gives you quick access to the EditPage:
javascript:void(location.href = location.href.replace("?","?edit="))
You can adjust this bookmarklet easily to have a different size for the text area in the editor:
javascript:void(location.href = location.href.replace("?","?rows=38&cols=135&edit="))
Of course you can modify this also to open another window for the EditPage
javascript:void(window.open(location.href.replace("?","?edit=")))
This version prompts you for the name of the page to edit:
javascript:var Pge = prompt("Page to edit?",""); if ("" < Pge) {location.href = "http://c2.com/cgi/wiki?edit=" + Pge;},
To use a new window for the editing,
javascript:var Pge = prompt("Page to edit?",""); if ("" < Pge) {void window.open("http://c2.com/cgi/wiki?edit=" + Pge);},
(but this doesn't maximize the new window in MSIE).