You need the full Acrobat product.
 
When you install it, in sets up a dummy printer.
 
All you need to do is 'print' your file to the PDF Creator and it will do the rest.
 
I think Distiller will do it (I haven't used it for a while), but it's not free. You'll need to buy it.
 
PDF is a fairly open format, and there are other products that will create PDF files. You should be able to find them if you search around.

If you're looking for free software, you can use Ghostscript ( http://www.cs.wisc.edu/~ghost/) but it's a hard to use for .PDF conversions -- you have to set up a PostScript printer driver, save the output to disk, and then convert the PostScript file to PDF.
 
WordPerfect 9 (2000) can also write .PDF files without needing Acrobat, if you're wiling to use a different word processor. It might be cheaper to just buy the standard WordPerfect Office 2000 and use WordPerfect to open the .DOC files (it should be able to read them just fine) and save them as .PDF files than to buy Acrobat.
 
Distiller is a more expensive version of Acrobat that can convert from PostScript files directly to .PDF files. If you don't know what this means, then you don't need it.

In Acrobat 4.0 you can open word docs and convert them to PDF
 
------------------
Frank
A+, Windows 98 and NT MCP

If you have Reader, you can convert documents to pdfs online via submission. The link is within Reader on the sidebar when viewing a pdf.

There are many tools with wich you can make PDF files, check out this site - http://www.pdfzone.com/products/software/toolinfo_convert.html
In addition, I would recommend you to check out this little program - http://www.jawssystems.com/products/creator_text.html
 
hope this will help