I am based in the US. If I wanted to offer web hosting to Asia, would I need another merchant account other than my US based merchant? Not sure how this money exchange works. Any advice would be greatly appreciated. Thank You

You wouldn't need another. Asia uses Visa, Mastercards, Amex as well which is truly international. There's no reason for another merchant account.

I am from Asia and when I purchase things over the web, I am usually charged US dollars using my credit cards. My bank would do the conversion to the local currency so you do not have to worry. The only time you need to worry is when you get international checks if they intend to pay in local currency.

The merchant account you have can handle credit cards from any countries and that is the beauty of credit cards anyway. After all, the credit card came about to allow people travelling overseas to make payment instead of carrying tons of cash with them.