Remittances meant for margin trading are a grey area - RBI has a few notifications that prohibit this but there are loopholes. So forex trading is a grey area. There are a few threads on this site that discuss this - do browse a bit.
The truth is you can also enjoy trading commodities / index futures on BSE / NSE/MCX/NCDEX. So if margin trading is your poison you need not go to foreign forex brokers.
BTW, for someone very new to trading, leverage acts a loss magnifier. A traders first priority is protection of capital and risk management. Do not let profitability and greed guide your choice of markets or systems.
I can personally tell you that commodities can be VERY profitable. For example I know of a friend who has just begun trading last week. He bought 4 gold mini contracts at 450 a few days back with a 20 tick stop loss. He sold out when gold hit about 800. That gives him a gain of 350 * 10 * 4 = 14000 Rs. Now that is a gain of about 30% in a few days. So dont be forced into thinking that you need to stretch hard and enter the currencies to make money.
DO understand that the players, their motives etc on the MCX are very different than the currencies. So you should choose one market / one instrument and study it for some time.
ITax would be the same for any market.
BTW, for people who are smart enough there currently exist structural inefficiencies in the mcx. But you must look beyond the obvious
Happy trading.