icon usage

does anyone know what the legalities are for using microsoft windows and office icons on a website or in a software package?
I have seen lots of people use ms icons one their websites and in their software. Is this ok to do?

I would personally side on the caution side. When using software, the EULA states its for x machines only and not to be copied elsewhere (except one backup). SO copyright applies to programs, help files, pictures, documents and icons

I would personally create one's own icons with the many Icon Creation programs that are out there...