Steve ham's and Puri Almansa Arribas' Flypiedrahita has tons of good information: 

http://www.flypiedrahita.com

 

The town of Piedrahita's facebook page:

https://www.facebook.com/ayuntamientopiedrahita/timeline

 

"Paralandia": Your guide Suby's webpage and facebook page:

http://paralandia.wix.com/paralandia

https://www.facebook.com/Paralandia-341002039407277/?fref=ts

 

Windtech Paragliders:

http://windtech.es/en/products/index.html

 

Videos of flying in Piedrahita

Martin Muller's "Let the day begin"

https://www.youtube.com/watch?v=GNBRyKzKmJ4

 

From ojovolador.com "Paragliding XC competition flying in Piedrahita 2009"

https://www.youtube.com/watch?v=ZfImcLzOrYg