Most US and Canadian providers offer cellular and data service for the Philippines. The problem is that carriers such as Verizon, Sprint and others charge a lot and offer very little. Cellular Abroad offers options that you will not find with your current provider, such as being able to have a local phone number, and with low and transparent rates.
Many phones and almost all smartphones have the capability of working overseas. Unfortunately, the carriers "block" the phones from being compatible with other carriers as they want to make the revenue when you travel abroad. Carriers charge huge premiums for roaming and in fact, unsuspecting travelers have often come back home to find that they have been charged many hundreds, even thousands of dollars in roaming fees. Luckily, there are alternatives. If your carrier is Verizon, most of their newer smartphones like the iPhone 5 and the iPhone 6 come unlocked. If your carrier is AT&T, Sprint or T-Mobile, usually your phone comes locked. If you are out of contract, the carrier will unlock it. Alternatively, you may have your previous phone which is surely out of contract and hence the carrier will unlock it. If you cannot get your phone unlocked or do not want to deal with it, you can also rent a phone or buy a phone.
If you are traveling to the Philippines for a short trip, maybe just a week or two, it makes sense to rent a phone. If your trip is longer, purchasing a cell phone makes sense.