With S-unno, you can use your android phone to make phone calls to any fixed or mobile number in more than 200 countries at absolutely low rates. Rates start from as low as US 1cents/minute. S-unno uses your 3G or WiFi connection to place these calls so that you can start saving now. Not just phone calls, S-unno offers much more SMS & cross platform Instant Messaging.
*Please note that using this application as your default dialer may interfere with dialing 911 emergency services.