The first suggestion is PDFCreator [1], an open source program that works by setting up a pseudo printer in your system. To create a PDF you just select the PDF "printer" and print to it. This means you can create PDFs from Word, Excel or any Windows program that allows you to print. The program has many useful features including the ability to encrypt the output PDF, store embedded metadata and to merge multiple documents into a single PDF.
A good second choice is CutePDF Writer [2], which is a cut-down version of the commercial CutePDF product. It works in a similar way to PDFCreator and it's free for both personal and commercial use.
Also to be commended is TinyPDF[3]. Unlike CutePDF it doesn't require the open source program GhostScript to be installed and it's also, er, tiny.
Perhaps the most capable of the free PDF writers is Primo [4]. It's packed with features including the ability to optimize output for screen, print e-book or pre-press, set metadata and the ability to set different security settings including the ability to create PDFs that can't be printed. Like PDFCreator it's a fairly hefty download though and possibly overkill for average home users who may be better off with CutePDF or TinyPDF.
If your need for a PDF writer is only on rare occasion then PrimoPDF also has a free online version where you upload your file, it converts it to a pdf and sends you an email with the link to download or open the file and save it locally. No local install, no changes to your system. For those who only create a pdf once or twice a week this might be the preferred method for you.
[1] PDFCreator
Website: http://sourceforge.net/projects/pdfcreator/
Author: Sourceforge Project
Date: Aug 25, 2006
Version Number: 0.9.5
Download Size: 12.6 MB
License: Freeware
Operating Systems Supported: All Windows versions
64 Bit Capable: No
Other languages supported: None
Additional Software Required: None – includes Ghostscript
Portable: No
Other Relevant Information:
[2] CutePDF
Website: http://www.cutepdf.com/products/cutepdf/writer.asp
Author: CutePDF
Date:
Version Number: 2.7
Download Size: 1.55 MB
License: Freeware
Operating Systems Supported: Windows 98-Vista
64 Bit Capable: Yes
Other languages supported:
Additional Software Required: GhostScript
Portable: No
Other Relevant Information: Ghostscript is no longer included in the download but must be downloaded and installed separately. There is a link on the page for the download.
[3] TinyPDF
Website: http://www.tinypdf.com/
Author: TinyPDF
Date:
Version Number:
Download Size: 586 KB
License: Freeware
Operating Systems Supported: Windows 2000 and later
64 Bit Capable: No
Other languages supported: None
Additional Software Required: None
Portable: No
Other Relevant Information:
[4] PrimoPDF
Website: http://www.primopdf.com/
Author: PrimoPDF
Date:
Version Number: 3.2
Download Size: 12.7 MB
License: Freeware
Operating Systems Supported: All Windows versions
64 Bit Capable: No
Other languages supported: None
Additional Software Required: Net 2.0 installs automatically if you don't have it
Portable: No
Other Relevant Information: No