Although you can export Pages documents to Windows-friendly formats, you might sometimes get caught in a bind and be able to send only the original .pages file to one of your Windows-using colleagues. Unfortunately, Windows applications can’t open such files. However, there is a workaround:
Pages ’09 files are actually archives. You can view the files within them if you change the extension of the Pages document file from .pages to .zip.
You can then unzip the file and view its contents. It will contain a QuickLook folder. If you open that folder, you’ll see the file Preview.pdf; that’s a PDF version of your Pages document. Your Windows-using friends can’t edit that file without a PDF editor, but they can read it and print it just fine.
This trick also works with Keynote and Numbers files. But it’s worth noting that it only works if the Include Preview In Document box was checked when you originally saved the iWork file.
It’s usually checked by default, however, so unless you unchecked it yourself, you shouldn’t have any problems.