wiringpi base web site
gordon drogon
the-gpio-utility
try this on the Pi
gpio -v
Might need to do the following first...
sudo apt-get install wiringpi
wiringpi pinouts
or better still :
download-and-install
or even better -> go here
choose wiringPI Then navigate to gpio and 'sudo make install'
check version with gpio -v : need >= 2.50