I was introduced to this good little app by my son a few months ago now and have been using it ever since.
What does it do? Well it enables you send and receive texts, Pictures, and all kinds of multimedia etc.. all for FREE!! (as long as you have a good data package) using your mobile.
The beauty of it is that if you have friends or family in other countries you can add their mobile number and if they use WhatsApp you can send them Text messages or Multimedia messages via your mobile at no extra cost..
It works on nearly all smart phones Blackberry, Nokia, Droid and IPhone
Pro’s : Its Free* and you can send all kinds of media to a mobile
Con’s : It does but a strain on your battery