An excellent tool for creating and converting PDF files, and the best news, its free!
PDFCreator is a free and easy-to-tool that can create PDF documents from any application which has a printing function. It provides professional results with a few clicks. To create a PDF file, you only need to send your documents to a virtual driver. With PDFCreator, it is also possible to create documents via the command-line interface. The generated PDF file can be emailed, printed and so forth. Moreover, you can merge several documents into a single PDF file for easy management.
This tool offers you several ways to protect your documents. The first one is to disable printing and changes to your documents. The second one is to use password protection. If you like, you can encrypt your files with 128-bit AES. Finally, to ensure that you are the author so that no one can modify the file, you should digitally sign it. Apart from creating PDF documents, it can also create documents with the following formats: PNG, JPEG, BMP, PCX, TIFF, OS, EPS, PSD, PCL, RAW, and SVG.
Yes, this software is Open Source. You are free to use PDF creator at home and work. The main differences between this version and the paid version are the lack of advertising, extended support network and some additional features which can be see on their website, here.