Just select your network from the list, pick a (Google) contact* from your contact list or manually type the recipients phone number then type your message and hit send! Wait a few seconds and you should get an SMS message confirming the delivery of the text.**
Currently supported Networks:
Virgin Mobile (UK)
Your network not listed? Leave a comment and we'll try and add it in future updates.
*If your contacts do not appear in the app, go to the People app on your phone, press menu, select import then copy all your contacts from Sim/Phone then export them as Google contacts. Your contacts should now appear within the app. (Courtesy Paul Lamont)
**Note: Delivery report SMS may not be free on all networks