Mac OS X has long had the ability to create PDFs of any printable screen. (Mac fans, just choose Print, then click the PDF button.) Some Windows applications create PDFs as part of their functionality; that option is often in the File menu or an export command. But PCs normally have to rely on a paid version of Adobe Acrobat to create PDFs. Here's how to add that Mac-like PDF "printing" into Windows for free.
Download and install PDFCreator. Then, like on a Mac, choose to print a document. Instead of selecting your normal printer, choose PDFCreator. Click OK, then click Save.
PDFCreator's advanced options can also be useful, such as requiring a password to read sensitive PDFs. In this situation, before you click Save, click Options. Click Formats, then click the Security tab. Check the box to Use Security, and click the option Password required to open document. Click Save. Continue saving the document as before. You'll be prompted to create the password.
The paperless office materialized, but PDFs help; I'll often save PDFs of electronic receipts instead of printing them out. PDFs also retain document formatting and are fairly universal files. Email PDFs instead of Microsoft Office files, for example, if the recipient doesn't need to make edits. They should be able to read your attachment on a mobile phone or PC without Office.
Zack Stern contributes regularly to PC World and other technology publications.