I'll not now go into the essentials of copy editing or plain English (I have some del.icio.us links for the plain English resources.) Instead, let's consider the PDF itself.
The Portable Document Format (PDF) has recently been made an freely-implemented ("open") document standard, cementing its position in the world of electronic texts. While most associated with its creator Adobe, there are a number of ways now to make a PDF document. Unfortunately, the all-too-common way is to drop a printed manuscript into a scanner and voila! -- you get utter crap with no underlying text. All you have is an image of text. It's like the fax machine has followed us.
I create PDFs in Linux two ways. The first uses a virtual printer through CUPS. (MacOS X uses CUPS, too, and I understand Mac users can do the same thing, but not being a Mac person, will have to defer to my readers.) Instead of a printed paper, you create a PDF file.
For Windows users, I commend PDFCreator. If you have an Ubuntu Linux install disk, you can use it after you have Windows booted up and download a number of Windows-only goodies; it's an incentive to introduce Microsoft users to try open-source software on their own terms and PDFCreator is among them. (Or at least this used to be true; if you prefer you can download just the Windows software as TheOpenCD here.) Or you can download just this program here.
The other way -- which I like a little less -- is exporting from the OpenOffice.org office suite. (The name's the URL and back.) The problem here is for Mac users without adding other software, but the derivitive NeoOffice project has made a new release and might be what you want.
Either way, you get good, clean PDF files.