I have found in Windows Live Writer that I am able to create a new Page, such as "About", but I cannot edit my existing pages. Matt mentions here an extension that would allow you to do it: http://wordpress.com/blog/2007/07/13/windows-live-writer-ftw/ It's the second to last paragraph of the post:
"A few weeks ago a new version of Windows Live Writer was released that supported all sorts of neat WordPress extensions to do things like edit pages..."
I have searched but I cannot find this extension. Any idea where I can find it?