I have bought a very small cell phone vibration motor. But I don't know how to drive it. Can I just use AC 3V to drive it?
No. Any mobile phone device is designed to work from DC, since they are not plugged into the mains!
The specs on that motor say 1 to 2V dc, 75mA nominal current, so any reasonable switching transistor could be used, like a 2N2222, but you need a low voltage supply, or use PWM at a low duty cycle with say 3.7V/5V/6V supply, as it won't handle 100% duty at higher than 2V