When I googled for "free xml schema editor" I got a lot of links that appeared to be just that. Did you do that search? Did you reject some of the links that it brought up? I don't really want to spend a lot of time repeating evaluations that you may already have done.
Edit: In fact I notice that the first link I get is exactly what you posted, "FREE XML Schema Editor - Graphical XML and XSD Editor, with Validator", even to the capitalization of those words and the punctuation. So I assume you must have done some searching already. [ July 09, 2008: Message edited by: Paul Clapham ]