How do I use I2C devices with Arduino?
Arduino have the Wire Library that communicate with I2C.


  This library allows you to communicate with I2C / TWI devices. On the
  Arduino boards with the R3 layout (1.0 pinout), the SDA (data line)
  and SCL (clock line) are on the pin headers close to the AREF pin. The
  Arduino Due has two I2C / TWI interfaces SDA1 and SCL1 are near to the
  AREF pin and the additional one is on pins 20 and 21. As a reference
  the table below shows where TWI pins are located on various Arduino
  boards.


Board   I2C / TWI pins


Uno, Ethernet    A4 (SDA), A5 (SCL)
Mega2560 20 (SDA), 21 (SCL)
Leonardo 2 (SDA), 3 (SCL)
Due  20 (SDA), 21 (SCL), SDA1, SCL1


You can take a look at , this examples.

Like @TheDoctor said:


  The I2C data lines both need resistors to 3.3V. This keeps them from
  drifting if they are disabled. Andy resistor value should work, but it
  is recommended to use one between 10k ohm and 47k ohm.