Tropo makes it easy to add voice, instant messaging and text messages
to applications. Use our simple API and the web development skills you
already know to build powerful communications applications. Create a
conference call with one line of Ruby. Answer the phone with a PHP
function. Phone calls, speech recognition, and SMS with no telephony
hardware, software, or special knowledge needed. Tropo's cloud API is
100% free for developers around the world. Create your first
application in less than 10 minutes at http://tropo.com/.