A basic ComputerCraft program that allows control of a turtle from a wireless pocket computer using Rednet client/server API

client.lua

--> Run this program on an (advanced) wireless pocket computer in your off-hand for best results
--> Replace 'id' with the id of the turtle - run the 'id' command in the turtle's shell

rednet.CHANNEL_BROADCAST = 8000
rednet.open("back")

print("Controller open on port "..rednet.CHANNEL_BROADCAST)

while true do
  rednet.send(id, io.read()) 
end

server.lua

--> This program must be run on an advanced wireless turtle

rednet.CHANNEL_BROADCAST = 8000
rednet.open("right")

print("Now listening on port "..rednet.CHANNEL_BROADCAST)

while true do
    local id,msg = rednet.receive()
    local action = "UNKNOWN"
    msg = msg:lower()
    for token in string.gmatch(msg, "[^%s]+") do --> split string by space
      if token == "w" or token == "forward" then
        action = "FORWARD"
        turtle.forward()
      elseif token == "a" or token == "left" then
        action = "LEFT"
        turtle.turnLeft()
      elseif token == "s" or token == "back" then
        action = "BACK"
        turtle.back()
      elseif token == "d" or token == "right" then
        action = "RIGHT"
        turtle.turnRight()
      elseif token == "up" then
        action = "UP"
        turtle.up()
      elseif token == "down" then
        action = "DOWN"
        turtle.down()
      end
      print("Received action "..action)
    end
    turtle.refuel() --> Infinite fuel!
end