Vonage has just rolled out new Android and iOS apps that do just that. The Vonage Mobile app offers free talk and text for corresponding with fellow app users worldwide by way of WiFi or data connection. Need to update app-less Auntie Em while backpacking through the Swiss Alps? The outfit says it'll save you 70% over major carriers and costs 30% less than Skype. For calls to folks without the app, users can add calling credit in either $4.99 or $9.99 increments right from the iTunes store or Android Market. The software also makes use of your existing number and extensive list of contacts without the need to create another username. Right now, calls to any phone in the US of A, Canada or Puerto Rico are free from the app for a limited time -- so long as you stay under 3000 minutes per month, of course.