It can be downloaded for free at: fireflyexperiments.com/
Firefly is a set of comprehensive software tools dedicated to bridging the gap between Grasshopper (a free plug-in for Rhino), the Arduino micro-controller, the internet and beyond. It allows near real-time data flow between the digital and physical worlds, and will read/write data to/from internet feeds, remote sensors and more. It also includes a Pachube reader.
Jason K Johnson [Future-Cities-Lab; CCA - San Francisco, CA]
Andy Payne [LIFT Architects; Harvard GSD - Cambridge, MA]