Whatever you do, do not send the Word file.
You see, Microsoft Word keeps a lot of the information that used to be in the document, stored in the file. There are all sorts of things that you think you edited out, but are actually still in the document. For instance, when SCO sent a Word file to Daimler-Chrysler to announce their suit, analysis of the file revealed that SCO originally intended to sue Bank of America. How professional does that make you look? What does that tell the defendants about you?
And even if you take all of that into account, there are interesting things to be learned from looking at the document properties. Such as the fact that you are not who you claim to be.
The solution is to send out your documents as PDF. It can be read on any platform with a freely downloadable reader, it can not be (easily) changed, and all of the hidden Word 'features' are stripped out of the file. PDF995 is a free PDF converter, which installs like a printer driver in Windows. Simply print your document (or anything else, really) to the virtual PDF printer, and it will be converted into PDF for you. It is ad-ware, but if you make a rule in your firewall that all network traffic from the PDF995-executable is to be blocked, you never see any ads.
Save yourself (and your boss) a boatload of trouble by using PDF for emailing your electronic documents.