If you are a Mac user we recommend one of the following solutions in order to run FieldWorks.
Parallels solution (most versatile, most expensive)
With a Mac that has at least 8GB or RAM, purchase Parallels (~$80 or ~40 for student pricing) and a Windows 7 or 8 license (~$100 for students). This allows you to run Windows software on your Mac. This solution would also enable you to run Phonology Assistant, Speech Analyzer and a number of other Windows-only applications. You can install FieldWorks and run it in its own Window while having full access to your Mac applications.
Bootcamp with Windows solution (less expensive)
Bootcamp is a built-in utility that comes with Mac OS X. It allows you to boot your Mac into Windows. You will still need to purchase a license of Windows 7 or Windows 8. Unlike Parallels, you only have access to Windows when you use Bootcamp, meaning that your other Mac applications are not accessible until you reboot into Mac OS X (at which point you no longer have access to Windows).
VirtualBox with Windows solution (less expensive)
VirtualBox provides a way for you to run other operating systems such as Linux or Windows. It will require some technical savvy to install and use but VirtualBox is free. In order to run Windows, you will need a Windows license.
VirtualBox with Linux solution (free)
Use VirtualBox to run Linux on your Mac and then install the Linux version of FieldWorks, available at http://fieldworks.sil.org. Requires more technical savvy than other solutions listed above but VirtualBox and Linux are free.