Example... this assumes that your external EEPROM has a device address of $A0 (see your chosen EEPROM's Datasheet) and is of the 24LC32/24LC64 type). SCL is the PIC pin you are using for the I2C Clock line, SDA is the PIC pin you are using for the I2C Data line.
Code:
	'
	'	Subroutine Writes BYTE to External EEPROM
	'	------------------------------------------
SetDataExternal:
		' I2CData - General BYTE variable
		' I2CDeviceAddress - Hardware Device Address - BYTE variable
		' I2CDataAddress - Address in EEPROM - WORD variable
	I2CDeviceAddress=$A0
	I2CWrite SDA,SCL,I2CDeviceAddress,I2CDataAddress,[I2CData]
	Pause 10
	Return
and the opposite to read...
Code:
	'
	'	Subroutine Reads BYTE from External EEPROM
	'	-----------------------------------------
GetDataExternal:
		' I2CData - General BYTE variable
		' I2CDeviceAddress - Hardware Device Address - BYTE variable
		' I2CDataAddress - Address in EEPROM - WORD variable
	I2CDeviceAddress=$A0
	I2CRead SDA,SCL,I2CDeviceAddress,I2CDataAddress,[I2CData]
	Return
For further information lookup the I2CREAD and I2CWRITE commands in your PBP manual and compare the examples against the EEPROM Datasheet.