If you are considering placing your module in Abeir-Toril, the fictional planet of The Forgotten Realms on which Faerûn is located, be sure to check out the wiki.
Abeir-Toril main entry:
http://en.wikipedia.org/wiki/Abeir-Toril
The Faerûn entry:
http://en.wikipedia.org/wiki/Faer%C3%BBn