UHH okay... my name is Ema and I didn't get to choose my name, it was given to me when I was born. So please don't be stupid, its obviously pronounced em-a. :)
For the countries where Ema is commonly used, the pronunciation given by LoQuiero is the most correct one. A fine alternative for Emma, easy to spell and not so overused. (Oh, and yeah, I can just see people lining up to joke about EMA money. /sarcasm).