U.S.A. AND OTHER COUNTRIES
If you obtain your money order from a post office make sure it's an INTERNATIONAL postal money order in US$. The color of the paper from the USPS is Pink.
Money orders from Walmart and banks have no special requirements.
Below is a picture of an International money order issued by the U.S. Postal Service. Please note that the USPS charges US$3.25 for this (as of 2003),
so it may be cheaper to send a cheque instead.