and Bochs: http://bochs.sourceforge.net
are free, but the emulation won't run as fast as in VmWare, and you may have more difficults to emulate such a big system (I've only used QEmu and Bochs on very small OS, btw, bochs is slower, at least two years ago). In VmWare it's really easy to install the emulated system, you've a GUI for it, where on the other free alternatives you don't.
Anyway, on QEmu homepage you've a list of supported system where you can see that Windows can be emulated: http://fabrice.bellard.free.fr/qemu/ossupport.html
Bochs should be able to handle Windows well also.
If only need to run a Windows app, you could use Wine.
Edit: took a some minutes to post this and some info was already answered on other posts.