This voice recognition software is the most powerful package available for the Mac, allowing both voice recognition (for the quick dictation of text) as well as hands-free control in many applications.

There is also a version of Dragon for Windows

Excerpt from product page description

Ignite productivity with fast, accurate dictation

Say words and watch them appear on your computer screen — three times faster than typing — with up to 99% recognition accuracy right out of the box. Correcting or revising your dictated text is simple with a new, more powerful correction interface that lets you quickly edit words or phrases. Dragon Dictate adapts to your voice and the words you use to deliver better recognition results over time. You can personalize Dragon Dictate with your own custom vocabulary of acronyms, proper names, and other unique phrases that you frequently use. Dragon Dictate can even adapt its format rules by detecting your format corrections – abbreviations, numbers, and more — so your dictated text looks the way you want it to every time. Review your work with Dragon Dictate’s Text-to-Speech feature, which reads back editable text for easy proofing or multi-tasking.

Ignite convenience using your favorite mac applications

Dragon Dictate for Mac goes beyond simple speech-to-text, and gives you control in more applications so that you can simply speak to do more than ever before. Use Dragon Dictate in MacOS with virtually any Mac application. Create and edit documents in Microsoft Word, TextEdit, Notepad and Pages, work with spreadsheets in Microsoft Excel and Numbers, create presentations in Microsoft PowerPoint and Keynote, manage email in Mail, search the Web or your Mac desktop, post to Facebook or Twitter, and more – all by voice. Dragon Dictate’s new Express Editor lets you dictate into a text field in any application on the Mac for which it does not have Full Text Control. After you finish dictating, simply transfer the text from the Express Editor to the desired application quickly and easily by voice.

Ignite proficiency & ease of use right out of the box

Thanks to the new interactive tutorial’s simulations, you can learn and practice good dictation, correction and editing habits so that you can create text efficiently within just a few minutes. Dragon Dictate’s help menu is within reach with a simple voice command, so assistance is always available when you need it.

Ignite freedom and comfort at your mac

Say goodbye to repetitive stress injuries. Use your Mac in a comfortable, ergonomic way without being tied to your keyboard and mouse. Open applications or folders, select menu items, click, or move the mouse, press keys, switch from one application to another or create custom voice commands to execute multiple steps by voice.