NewerTech® - Voyager Q “Quad Interface” FireWire® 800/400/USB 2.0/eSATA - SATA I/II Hard Drive Docking Solution
http://www.newertech.com/products/voyagerq.php

Recommended by James Andrewes.

FireWire 400/800 USB 2.0 eSATA dock for SATA I & II internal hard drives

Hard drive dock sata usb firewire 400 800

FireWire SATA dock from the same folks that make the miniStack.

Just insert any standard 2.5" or 3.5" SATA I/II hard drive with up to 2.0TB capacity into the compact docking base and select one of the four interfaces supported by your Mac® or PC for the fastest data transfer performance. Then, start reading and/or writing data to the docked hard drive. There’s nothing else to install or configure!

Suggested by John Able and John Stevens