Google announced a few days ago that third-party apps will no longer work with Google Voice as of May 15, 2014. I already updated my Obihai post, but this will also affect those people who make voice calls over data with GrooveIP or similar smartphone apps.
The good news is that Google has stated that it wants to fully integrate Google Voice into their own mobile apps so that you can make free voice calls and SMS over data. (Well, I’m not sure about the free part. Given how late it is in the year, I think it will stay free for another year at least.)
The Google Hangouts app for iPhone/iOS has been updated to add free voice calls over WiFi and cellular data (anywhere in the US and Canada) and Google Voice integration. I downloaded it and it worked well. Incoming calls to my Google Voice number rang directly to my phone screen. I can make outgoing calls from inside the Google Hangouts app, and the person I call sees my Google Voice number on their Caller ID. Voice quality was good, although I was on WiFi at the time. So far, SMS/MMS/voicemail are unavailable.
This makes Google Hangouts a good alternative for iPhone owners on the T-Mobile $30 a month Unlimited Data Plan or for those on minimalist pay-as-you-go plans as you can make free voice calls over WiFi. Works on iPod Touch too.
Similar functionality is supposedly coming to Android phones “early next year”. I would hope this means before May 15th.