OTO is a great application that provides internaional calls from KOREA.
OTO lets you make international calls based on Korean telecommunication company (SK/KT/LGT).
OTO international call is..
a free international call service with no international call charges
A local call fee from the payment system of the userís smart phone occurs, and there is no duplicate billing.
-mobile & phone
OTO free international call Screenshots
OTO free international call free for your Android phone