MCP4822 dual 12-bit Digital to Analog Converter (DAC) chip.
The MCP4822 is a dual 12-bit Digital to Analog Converter that is controlled via an SPI interface. It is available in PDIP, SOIC or MSOP packages. The documentation for the chip is available at Microchip's MC4822 page.
The range also includes 8 or 10-bit DACs, which this library could easily be converted to.