Looking for a free texting app that works for other platforms like iphone,android, BB

[sugaryling]

What do you guys use for texting besides the built in texting features on out TP2? The reason I asked is because I need to text internationally and as long as the cell phone has a data plan, it's free texting for the sender and recipient. Programs like "whatsapp and Pingchat works great on iphones, BB and android, but it doesn't work for Windows phones. So what do you guys use? I don't need to an app that includes chats like AIM or google chat and etc. Just need to text. Thanks!