From November 8th through November 30th, T-Mobile will not only allow free calling and texting from the U.S. to the Philippines, the carrier will also wipe out roaming charges for its prepaid customers already in the area, or who are traveling to the region for rescue efforts. Those T-Mobile customers who often make calls to the Philippines will receive an email from the carrier carrying more information.
T-Mobile is waiving and crediting fees for all calls and text messages by current customers placed to the Philippines from November 8 through November 30, 2013. GoSmart Mobile, Brightspot (Target) and Walmart Family Mobile customers will receive credits for calls and text messages to the Philippines. Prepaid customers will be able to make calls and send text messages to the Philippines during this timeframe, free of charge, if their service is capable of international calling and texting."-T-Mobile statement
source: T-Mobile via TmoNews