At the time of this article (July 2011), vReveal is available on both 32- and 64-bit versions of all recent Windows OSs: Windows 7, Windows Vista, and Windows XP.

Windows 7 is the officially supported OS (both 32- and 64-bit version).  While things work great on Vista and XP most of the time, there is sometimes a problem with a 3rd party compontent that we use (e.g., GPU driver) that may prevent vReveal from operating properly.  

vReveal's video processing pipeline is relying heavily on Microsoft's DirectShow framework and porting to other OSs (like OSX or Linux) is not a straightforward task. We will keep looking at opportunities to support vReveal natively on these platforms, but there are no immediate plans for OSX or Linux version of vReveal. 

In the meanwhile, vReveal is tested to work well both in Boot Camp (on Mac systems) or in a Virtual Machine (e.g., VMWare or VirtualBox). If you are running OSX or Linux and have a Windows Virtual Machine, you are welcome to try vReveal -- you can get it for free at www.vreveal.com/download.