SharePort also allows (trusted) friends on my network to fire off files to a printer connected to my router via USB. The beauty of SharePort is that it knows when a print job is finished and automatically disconnects users from the USB-attached printer.
The pins on the Arduino can be configured as either inputs or outputs. This document explains the functioning of the pins in those modes. While the title of this document refers to digital pins, it is important to note that vast majority of Arduino (Atmega) analog pins, may be configured, and used, in exactly the same manner as digital pins.
Pololu DRV8835 Dual Motor Driver Shield for Arduino. This small shield is an easy, economical way to control two small brushed DC motors with an Arduino or Arduino-compatible board. Its integrated DRV8835 dual motor driver allows it to operate from 1.5 V to 11 V, making it a great control option for low-voltage motors.