This IC will allow you to expand the number of input and output pins on your microcontroller. It uses 3 I2C pins to give 8 general purpose input/output pins. It even includes a configurable interrupt outputthat can be set as active-high, active-low or open-drain.

44 page data sheet available for download.

Features:
1.8 -5.5VDC Input
Low standby current (less than 1A)
8 Configurable Input/Output Pins
1.7MHz High Speed I2C Interface
External Reset Input