The main resources for learning drow are roleplaying sites, though these tend to teach Low Drow, which was originally described in TSR's Drow Dictionary. The vocabulary between Low Drow and High Drow is the same, but the grammar of Low Drow is far more simplistic.
One site where one may learn the basic grammar and some basic vocabulary in Low Drow is the website for the Chosen of Eilistraee.