Its possible to use a Google Android Phones' internet connectivity to make low cost or free VOIP phone calls.
An Android phone can make Internet connections either via the cellular data networks EDGE, 3G, CDMA, or via WiFi
Using VOIP over the cellular network may violate your cellular provider's terms of service — check your contract first.

News

• 2011-02-17 - Voxtrot launches a beta of seamlessly integrated free calling for Android http://blog.voxtrot.com/the-start-of-something-voxtrot-beta/
• 2011-01-05 - OnSIP team provides extensive review of native SIP support on the latest Gingerbread Nexus S. SIP on Android Nexus S
• 2010-01-05 - MO-Call now supported for the Samsung Google Nexus S Samsung Google Nexus S VoIP
• 2010-12-02 - MO-Call now supported for the HTC Desire Z and HTC Desire HD HTC Desire VoIP
• 2008-10-24 - iSkoot announces support for Android News story
• 2008-09-11 - German court bans VoIP on iPhone by request of German provider T-Mobile.

FAQ

VOIP Native Applications for Android

• 3CXphone for Android free SIP phone for Android phones
• Android VoIP from MO-Call
• csipsimple - Exciting new project with one of the best Android SIP Implementations
• ENUMDroid Adds ENUM (E.164 Number Mapping) on-the-fly querying support
• IMSDroid - High Quality Video SIP/IMS client for Google Android
• iSkoot Skype on your phone
• Sipdroid SIP client for Android
• SIPez provides custom SIP clients for Android supporting wideband and HD voice
• Skuku has a VOIP client for Android on the Android Market

VOIP Web Applications for Android

• JAJAH.Mobile Web from Jajah
• Phonegnome
• Raketu
• RF Dialer web based dialer - works with most VoIP providers, Asterisk, and Skype from RF.com
• Talkety

See Also

• Wireless VOIP
• Bria Android Edition reviewed by the team at OnSIP.