The OpenLog module is a quick and easy way to add logging to uSD card to your project. Place a simple text file on your uSD card to configure the comm parameters, then feed UART data into the RX pin. The OpenLog will simply copy the incoming serial data to files on the uSD card. Firmware is Arduino based and is available in case you want to modify it in any way.
OpenLog hardware and firmware are released under the Creative Commons Share Alike v3.0 license.
Based on OpenLog by SparkFun