Andrew Rohne posted another article on Bus Pirate Demo Board I2C showing the MCP4725 digital to analog converter and the PCF8563 real-time clock. Check out the part A here.
Like the last post, the ground and Vin need to be connected, and VPU (the pull-up resistors) need to be connected to the Vin as well. CLK on the Bus Pirate needs to be connected to SCL, and MOSI on the Bus Pirate needs to be connected to the SDA pin. There are other connections that will be necessary and will be different for each.
Digital to Analog Converter-
The additional connection that needs to be made for this is the ADC connection on the Bus Pirate should be connected to the OUT pin on the demo board. This will allow you to see the output. As shown in this video by Mike Parks, it is pretty easy to address and use.