Brainstorming Arduino portable texting machine


I was looking to make a small portable, wireless texting device kind of like a phone. I am not exactly sure what to use for sending and receiving the information, but was originally thinking to maybe use an FM transmitter of some sorts. Does anyone know how far the an FM transmitter could reach without consuming a ton of power. I wasn't sure if I wanted both arduinos (Mega) on at the same time. So maybe I would have to get a third which would be on at all times and sit in a central location to receive a text. When the other arduino is turned on, it would send the text to the second arduino.

Another possibility I thought of for the data transfer was maybe to use a walkie talkie transmitter, but I am not sure how to implement that in an arduino.

What I hope to achieve: 1. possibly a one mile radius range 2. portable 3. lcd display 4. buttons (either keyboard or phone style keypad) 5. small (fits in a backpack's water bottle pocket) 6. power saving

Any comments, Ideas, or the do-ability of my plan would be very much appreciated. Thanks

Thanks for the reply,

I was just looking for a little project to work on with the arduino Mega and at the same time basically make a free text transmitter. Do you think it would be possible to use an old walkie talkie for this? Because if im not sure you can send stuff from one cellphone to another without a tower.