You may buy your BrainStorm licence at fifty percent off the normal price at http://www.brainstormsw.com/buyref.php. Please have your discount code to hand.
If you are new to BrainStorm, you may find the following pages of interest:
The Home page is the best place to go for an overview of the latest version of BrainStorm.
A "Benefit Matrix" at the foot of that page leads to a whole bunch of application-specific write-ups and user stories.
"BrainStorm in Action" explains key features of BrainStorm in pictures.
The Download page is where you can get BrainStorm and, optionally, a free diary generator