USB/IP Project aims to develop a general USB device sharing system over IP network. To share USB devices between computers with their full functionality, USB/IP encapsulates “USB I/O messages” into TCP/IP payloads and transmits them between computers.
Official site: http://usbip.sourceforge.net/
Example: http://howtoforge.org/how-to-modify-your-gnu-linux-box-to-serve-as-a-usb-over-ip-server