I am building a robot (a robot airplane) and i don't know what circuit i should use to make it wireless. Right now I am planning to use a DTMF circuit where i control it by mobile phone. But putting a mobile phone on my plane make it heavy and reduce the efficiency. can you suggest me any alternative for mobile phones and DTMF?

 

It's a pretty complex process.
There are many prebuilt solutions.
http://www.towerhobbies.com/products/futaba/surface_system_index.html
http://www.pololu.com/catalog/category/12

You'll need a controller and some servos.

Google with
Radio control controller servos
and you'll see many solutions.

 

Flying distance from controller?
bluetooth/wifi?

 

Maybe some infrared? I know you could probably get few hundred feet out of some higher power systems, and you could use something simple like an arduino to interpret the signals and control the servos!

Oh wait i just realized you'd probably be outside... Scratch the IR

 

Check out the Arduino Wireless Shield, it is super easy to use, and will also provide an easy platform to control servos and other rc components. It has a range of 100m outside.

http://arduino.cc/en/Main/ArduinoWirelessShield