...card when traveling to the US? Most travel sites accept credit cards only from the US and Canada and don't accept credit cards from the Philippines, even if by they're Mastercard or Visa.

You can use www.travade.com. They will accept credit cards from anywhere in the world. Also when you are searching international flights, I would recommend clicking on the little blue writing that says 'International Flight Search' before trying the main search method.

It is a great site with some really good deals.