manufacturer part number: TLC5940NT
The Texas Instruments TLC5940 is a 16-channel PWM capable LED and Servo driver with 12-bit duty cycle control (0 - 4095), 6-bit current limit control (0 - 63), and a daisy chainable serial interface. It can be used to expand the number of PWM outputs available on your Arduino or other microcontroller.
Acting much like a shift register, but able to sink more current, the TLC5940 IC is perfect for driving large RGB LED displays, multiple servos, or other devices suitable for PWM control. The ICs can be daisy-chained, enabling you to control far more than 16 channels from a single microcontroller.
This is the easy to use, breadboard friendly, DIP version of the TLC5940, it comes in a 28-Pin package. Since this IC acts as a current sink, please be sure to use it with common-anode LEDs - you will have unexpected or non-functioning results if used with common-cathode LEDs.
An Arduino Library is available here: https://code.google.com/p/tlc5940arduino/, and example sketches are plentiful on the web.
We use the same IC here to run our RGB LED display in our LED section.