Most Arduino boards have a 3.3V regulator on board. The pin that says "3.3V" on your Arduino board is an output. You can use that for the sensor.
To read and write the registers of the sensor, you need the I2C-bus. This bus uses two pins: SDA and SCL. This is a digital bus. The SDA and SCL happen to use analog input pins 4 and 5 (although the I2C-bus is digital and not analog).http://arduino.cc/it/Reference/Wire
If you look the three bottom functions in my code at: http://arduino.cc/playground/Main/MPU-6050
You will see that they implement the I2C-communication to the sensor, using the Wire library. You don't have to know how I2C works, you can use those three functions.