Is there any SMS through data app that is available for iPhone and Blackberry?

I know there's the app called Ping! for iPhone that allows the sending of SMS messages over your 3G connection, therefore it doesn't count as a text message and it acts pretty much the same as the regular iPho开发者_StackOverflow社区ne texting software. Is there any app like this that's available for both iPhones and Blackberrries?

Google Voice allows you to send and receive messages through a web frontend. Because it is just a web page, it should work on any phone with a data plan. More info here: http://www.google.com/googlevoice/about.html