What do Hinduism, Buddhism and Sikhism say on the subject of gambling?

According to the diatomic religions is gambling a sin, and if so, would FX trading be classified as a form of gambling?

No such thing as "sin." That's a notion of violating some divine law. Gambling is an incredibly efficient way of losing your rent money, though. Best not to do it.

The Buddha advised against it in Sigalovada Sutta (Digha Nikaya 31):

"There are, young householder, these six evil consequences in indulging in gambling:

(i) the winner begets hate,
(ii) the loser grieves for lost wealth,
(iii) loss of wealth,
(iv) his word is not relied upon in a court of law,
(v) he is despised by his friends and associates,
(vi) he is not sought after for matrimony; for people would say he is a gambler and is not fit to look after a wife.
(e) "There are, young householder, these six evil consequences in associating with evil companions, namely: any gambler, any libertine, any drunkard, any swindler, any cheat, any rowdy is his friend and companion. "

http://www.accesstoinsight.org/tipitaka/dn/dn.31.0.nara.html

EDIT--TD? Really? I really am starting to understand why some of the people that frequent R&S are so mean-spirited now.

it doesn't matter all i know is m not sure if its a sin but i know its wrong to gamble with.. so dint u ll regret it later... for sure...

Gambling is not a sin according to Dharmic religions. Pandvas played gambling and they lost. It is a loose rs game. Dharmic religions say do not gamble it means use your life for good things. FX trading is a business not a gamble. Earning by hard and honest work is good but by cheating is a gamble. Humans are gambling when they indulge in falsehood and forget True Lord.