[amper5and]

+1 for GV. What's cool is that there are libraries in many languages to allow you to use it in creative ways:

* java: http://code.google.com/p/google-voice-java/

* C++: https://github.com/mastermind202/GoogleVoice

* C#: http://code.google.com/p/sharp-voice/

* obj-C: https://bitbucket.org/joeygibson/gvoice/wiki/Home

* Python: http://code.google.com/p/pygooglevoice/

* PHP: http://code.google.com/p/phpgooglevoice/

* javascript (node.js): https://github.com/amper5and/node-google-voice

I dont know how many of those are still maintained. Disclaimer: I am the author of node-google-voice, which is still maintained.

[christiangenco]

Don't forget ruby: https://github.com/jeffrafter/google-voice

Though now it's looking a bit stale. Google CL needs to put some pressure on the rest of google to open up more APIs.