For using Crazyremote with 3g you need to open ports on your router. Go to Crazyremote server on you PC, -> Remote , then check Setting your router automatically
I haven't tried anything else since my Kindle Fire isn't rooted but this works great for simple stuff. You can't play or turn the camera very well but I can click, type, turn sharp or smooth pixels on/off, and hit hotkeys. Main product page for Splashtop Remote Desktop All you need is an account and both computers connected to the internet under the same username. So simple, 2 clicks and I'm watching my bot in class.