I have moved to OS X, and although Microsoft's Office software is brilliant on Windows, on the Mac its usability leaves something to be desired compared to Apple's own counterparts (Pages, Numbers and Keynote) which, although not containing as many bells and whistles, still provide any features I need to use.

So I now open all my existing .docx files in Pages (which can open it natively), where, once saved in the application, saves it to a .pages file by default.

What is the easiest way then, to open .pages files on my Windows computers (ideally, a similar automatic process in the reverse)?

Is there a downloadable Microsoft Word add-on (like the one that opens and converts newer versions of office files than the version you have installed), or a third party Office add-on (whether free or paid), or some other nifty tool to one-click / auto-convert .pages files to .docx files in Windows?