1) Adobe Acrobat PDF - What is it? What is it good for?
PDF stands for Portable Document Format and it does just that. If you create a Microsoft Word document and want to share it with a colleague who doesn't have Microsoft Word, how does that person read the file? Perhaps you've created a document that has a set of fonts included in it that your colleague may not have either. Acrobat PDF maintains fonts, layouts and page integrity of any of your documents.
Using a free Adobe Acrobat Reader, your colleague could review your paper without editing the text or having to worry about downloading and installing new fonts. Acrobat PDF files can be viewed on Mac, PC and Unix - all using the free Acrobat Reader.
2) Why not use a postscript viewer?
People have used postscript viewers before such as Ghostscript with GhostView. However, these programs were never very stable, they could be difficult to install and the user interface was not friendly.
3) Adobe Acrobat PDF Macros for PC versions of MS Word and Excel
4) Converting MS Word document to Adobe Acrobat PDF
5) Acrobat Exchange / Acrobat Reader
6) Overview of Acrobat Exchange Window and Buttons
7) Adding Functionality to your PDF file
8) Web Samples of PDF in use