The EiBotBoard (EBB) was originally designed for the Egg-Bot project. It is a small (2.2" x 2.2") two channel stepper motor driver board with USB microcontroller. It is based on the UBW board and supports all of the commands that the UBW does (for the most part), plus several extra, like stepper motor commands and RC servo output commands.
The EBB also has commands to drive up to 7 RC servo motors at the same time! While the EBB has a built-in 5V power regulator for the RC servos, if too many servos are connected you may need to use the additional power input circuit on the back of the board to provide additional power.
The idea with this board is to have a simple way to control two stepper motors from a PC over a USB connection. This is accomplished by two microstepping chopper stepper motor drivers and a small Microchip PIC microcontroller that has USB support. When you plug the EBB into a PC (Windows, Mac or Linux), it will show up as a serial port. You can easily type commands to it using a terminal emulator, or write your own application to send commands for moving the stepper motors.