Texdro! I love this app. It allows you to link your phone via wifi to your pc and then when an SMS comes in a notification appears on your PC desktop. You can type in the notification window on your PC and it sends the SMS back to the recipient! It works exactly as I envisioned an app that would do this should. The free version will link your phone via wifi only but their is a paid version that will work via USB or Bluetooth too.