Most probably yes. FlairBuilder uses Adobe AIR to run on Windows, Mac OS X, or Linux. If you don't have Adobe AIR installed, it will be installed for you.
No. The online and desktop viewers are free to use. However, you will not be able to make any changes to the project files.
The online FlairBuilder viewer available at http://share.flairbuilder.com/ offers you a simple way for your clients or team to visualize the wireframes/prototypes you have created using the desktop version.
With one click you can share your project straight from the application. The project will get uploaded to a secure location, and an URL will be generated. You can share that URL with your team.
The desktop application gives you a one click sharing option. In the application's toolbar, at the end, you have a button which will let you quickly share a project with the online viewer.
Upload the project file to a location visible from the internet, such as: http://www.mycompany.com/projects/myproject-v1.fbp
Send your clients an URL in the following form: http://share.flairbuilder.com/?url=YOUR_OWN_URL_HERE.
