My latest project, SwitchCoder, allows you to write voice and SMS applications in JavaScript and have them run from inside the phone company. Check out our intro video:
Getting up to speed is easy. Here's a video showing how to create a group SMS application using SwitchCoder.
You can invoke SwitchCoder scripts three ways: by calling a script, sending an SMS to a script or invoking a script over the web. Here's how that works:
Sign up now. We give you $10 of free credit so you can buy numbers and try it out. Be sure to let me know what you think about it!