For Nuance applications and software to work properly, a Windows environment is required. Nuance does not run natively in an Apple operating system. Officially, Apple computers are unsupported and no formal testing has been performed to ensure that the Nuance application suite works in OSX.
With that in mind there are several applications available that will emulate a PC Windows environment to various degrees. One of which, and the only dual boot option, comes with Apple OSX 10.6 Snow Leopard for Intel-based Macs. Apple Boot Camp will allow a user to split an existing HDD into two separate partitions, one for Apple, and one for Windows. Boot Camp is capable of supporting Windows XP, Vista, and 7. A dual boot solution has the advantage of requiring the least amount of configuration for hardware devices and peripherals. Disadvantages include having to split up your disk space, and in order to switch between Windows and Apple applications, the user must restart the computer and log into the other operating system.
Apple has additional information about the Boot Camp application here: http://www.apple.com/support/bootcamp/
The second option is to use emulation software to run Windows inside the Apple OS. This is in contrast to the dual boot option where Windows and Apple OSX are running separately. This makes switching between Apple and Windows application much easier, but running two operating systems at the same time can consume a large amount of system resources leading to overall lower performance. This is particularly true of older systems.
Additionally, purchase of emulation software does not include a copy of Windows. OEM installation disks, such as those that might ship with a pre-built PC such as may be purchased from Dell, HP, IBM or other manufacturers will not work. (This is also true for users with Boot Camp) Thus, the purchase of the emulation software represents an additional expense.
Nuance offers a brief tutorial for VMware Fusion here: Nuance Running On A Mac
A second option is Parallels for Desktop: http://www.parallels.com/products/desktop/
Users who are installing emulation software who have Intel-based Macs most likely meet any hardware requirements, but before purchasing any software Nuance always recommends that you check your current hardware configuration against the minimum requirements the software developer has published. Minimum requirements can be found on the box, or website of reputable sellers.
For installing Parallels, no better guide can be found than that written by the developers who created the software. Full documentation can be found here: http://www.parallels.com/products/desktop/resources/documentation/
If you're uncomfortable installing or configuring complex software an Apple Certified Technician will be qualified to assist you. An Apple Service Provider can be found here: http://www.apple.com/buy/locator/service/
Installation of 3rd party software is generally not covered under Warranty. (If applicable)
Lastly, with either Boot Camp or Emulation software you must decide what version of Windows you are going to install with it. Your Apple PC must also meet the minimum requirements to the Operating System that you choose. While most emulators will support older version of the Windows OS, Nuance requires Windows Vista, Windows 7, or Windows 8. Both 32-bit and 64-bit versions of the OS are supported.