One thing that users of Mac OS X systems have that Microsoft Windows users did not is the ability to create/save PDF files on the fly. Historically, Microsoft never provided PDF creation functionality in Windows. If you want to create a PDF document, you either have to shell out big bucks for Adobe Acrobat software, use Corel WordPerfect (which does have a save as PDF function), or install one of the many shareware/freeware apps. The latest SP 2 update to Microsoft Office 2007 finally includes PDF functionality (you can also download and install an add-in for Microsoft Office 2007 directly from Microsoft's download site).
But what if you don't have Office 2007 or want more options for creating/saving PDFs in Windows? My preferred solution is to install the open source freeware PDF Creator. PDF Creator is a GPL-licensed open-source free software for converting documents into PDF format on all Microsoft Windows operating systems (Windows 95, 98, 2000, ME, XP, Vista and Windows 7 beta). Once installed, it allows a user to select PDFCreator as their printer, permitting almost any Windows application to print to PDF.