Here's an interesting new service. VoxOx, which we called "Skype on Steroids" a few months ago, just announced a feature called SMS Callback, which supposedly allows you to place an international call, from any mobile phone around the globe, for just a few cents per minute.
You send a text message to a special VoxOx number, and wait for a call back connecting you with the person you're trying to reach. You avoid paying international rates because you're simply accepting an incoming call. And you don't even need Internet access. Setting it up requires a rather involved process, and it seems like there are multiple moments where something could go wrong, severing the call before it even begins. Nevertheless, it'll be a great deal if it works. Learn more here, and if you try it, tell us what you think.