This is a common problem in the world of email attachments, actually, and it all comes from an mismatch between what the email program wants to do and what you want to do. When I use Microsoft Entourage, for example, it automatically puts all attachments in a specific directory for neatness, and hands that version of the file, in that directory, to Microsoft Word, which merrily lets me edit and save changes without a glitch.

What you need to do is learn where it's saving those files, and fortunately that's easier than you realize. To figure out the directory, simply double-click on a Word attachment in your email program to launch Word, then immediately choose File --> Save As... and here's what you'll see:

Click on the small downward pointing triangle immediately adjacent to the file name to open up the dialog box, then click on the directory name. You'll be shown the exact location of the folder where your email program is saving attachments:

That answers the question of "where are those pesky files being saved?" and I'll note a quick Mac shortcut: if you want to save the edited file on your Desktop instead, simply press Cmd-D (or cloverleaf-D or apple-D, depending on how you think of that key on your keyboard!) and you'll be instead looking at your Desktop. Click "Save" and now you have the edited copy on your Desktop, easily found later.

Another way to deal with this is to drag attachments out of your email program and onto your Desktop before you edit them. Now there's no issue because you have a clean copy. You can also do that with the "save attachment as..." feature (or "save" button) in the email program itself, of course.

Finally, any time you have a file you've edited in a Microsoft Office application like Word or Excel, you can always just re-open the application and look for the most recently edited files list on the File menu. Find the filename you seek, open it up, then go to "Save As..." and resave it in a known location. Easily done!