The FR Arholly used comes from Forgotten Realms. Faerun map is based on a role-playing world which has been detailed out in many books and adventures. Numerous fantasy books also take place in that world.
This page:
http://www.geocities.com/Area51/Cham...00Deities.html seems to have descriptions of the deities, but the rules are something else than the D&D Forgotten Realm officially uses.