This product is he World of Gaianar RPG's built in setting translated into the Wizards of the Coast D20 game system. While primarily designed for d20 v3.5, some notes for v3.0 compatibility are included.
It is available on the Gaianar website as a downloadable Microsoft Word document.
From the summary at the start of the book:
Gaianar (pronounced “guy-nar”) is a fallen world that has been reduced to a pre-industrial state by warfare that swept through the realms many years ago, slaying millions. After the wars, Gaianar was catapulted back to an era in which gunpowder and firearms are considered the height of practical technology, steam engines are a wondrous marvel, and magical and spiritual forces that were previously discarded in light of science have returned with a vengeance.