San Diego-based VoxOx, a consumer-focused, voice mailbox and unified communications service, announced this morning that the firm has lauunched a new feature which allows users to make low-cost, international phone calls. The firm said it is targeting summer travelers with a new SMS callback feature, which connects users with a cheap, international phone call through a SMS message. The new feature allows users to send an SMS message which will trigger the service to call and connect a person with the international number desired. VoxOx is a subsidiary of Telcentris.