The Looking Glass is located on the sea-bed at approximately 60 feet (18m) depth, some 600 feet (182m) from the beach. The station is used to jam communications going to and from the Island. The station receives power from the cable that Sayid discovered in the episode "Solitary".
Just warning you, that if you haven't watched the whole show might see some information before you are ready. To help with that we have this nifty filter. Just set it to the episode you you are upto, and we'll do our best not to spoil anything.