What Nigel was saying is that with a number of I2C eproms on the market (I believe all Microchip eproms can do this) you can hook multiple chips to the same I2C bus. Externally by way of 3 pins, you can give each eprom a specifice address or "code word" if you prefer. All I2C devices have to have a unique "code word" in order to allow multiple devices to exist on the same two wires. What happens next is in the firmware of your PIC. When the PIC issues its first data transfer over the I2C bus, it first transmits the "code word". Every device on the bus receives the "code word" but only the one with the same code will respond to any further commands until you stop your data transfers by setting a "stop condition".
This bus arbitration is handled by the microcontroller. Speaking from experience, it is VERY convenient to use a microcontroller that has a hardware I2C controller built in. It will make your life a lot easier.
-Bill