Who doesn't use USB devices? Printers, flash drives, and external hard drives, and even novelties like mug warmers use the Universal Serial Bus port. With the exception of the RJ-45 network cable and the classic 3.5mm sound connections, USB is the one port that hasn't undergone a major physical revision since it was created in 1996. Video connectors have changed from VGA to DVI, Serial and Parallel port connections are now purely for legacy devices, and even Firewire connections are now outdated. Firewire was originally for Macs, but since the release of USB 2.0, even the hardware-specific Mac market couldn't deny the dominance of the USB connector.
USB 3.0, aka "Superspeed USB," is the next upgrade to the connection. The upgrade is mainly a major increase in speed. USB 2.0 had a maximum transfer rate of 480MB/s, while USB 3.0 will top out at 4.8GB/s - 10 times faster than its predecessor. However, the engineers at Intel also managed to add more power to USB powered devices like iPods. They achieved these two improvements by adding two more connections to the regular 4 prong connector, making a total of six. The Superspeed connections will also be backwards compatible with USB 2.0, 1.1, and 1.0 just like the previous revision was older devices.
The earliest that consumers will be able to experience the 10x increase in speed will be in 2010. The 'spec,' or standard is nearly finished. Of course, by 2010, HiDef video and external hard drives will be common, and the increased bandwidth that USB 3.0 provides will be essential to reduce wait times. So in under a year you may be able to copy your entire music library onto your iPod in under a minute, or move hundreds of movies to your hard drive in under ten, and you'll have USB 3.0, or "Superspeed USB" to thank.