Thanks, that helped me a bit. But I don't get this. Why does this link says pwm functionality is disabled on pins 9 and 10 if we use library :s . What does it mean ? And i connected it on pin 6 and servo motors moves but very strangely. http://arduino.cc/it/Reference/Servo
It means PWM is disabled on pin 9 and 10 if you use that library. It can't be stated any simpler.
On standard (not Mega) Arduinos:
timer0 does PWM for pins 5 and 6, and also does the timing for millis(), micros(), delay() etc
timer1 does PWM for pins 9 and 10
timer2 does PWM for pins 11 and 3
The Servo library takes over timer1 completely, no more PWM on pins 9 and 10. Simple.