Make Free Phone Calls with Google Phone Android

You can do free voice-over-internet phone calling through your cellphone. On an Android phone.

you can use the Gizmo5 service, Google Voice, and a free application to call anyone for free.

A free, open-source, and unofficial Android app, Guava, gives any Android phone the ability to make and take calls over Gizmo5's VoIP service, connected through a Google Voice phone number. It works over Wi-Fi, 3G, or, for the daring, Already HTC Hero, Dream are running on Android seems you can use this service in your existing Android enabled HTC phones.


What all you need to do this

Android-powered phone: P HTC Dream (T-Mobile G1), Magic (T-Mobile myTouch 3G), or Hero should work.
Google Voice and Gizmo5 accounts : You'll have to hope for an invite if you haven't gotten your Google Voice account yet, while Gizmo is much easier to obtain. click the stand-alone Guava link to download the .apk installer.
Wi-Fi or 3G service: At least to test out Guava and make your first test call. You can set Guava to call over EDGE connections, and even specify how many reception bars are required to try a call, but it's likely not worth the hassle.