Here is an example of the Double Dig process used to loosen compacted soil with hand tools. Double Digging is recommended by John Jeavons, in his book How to Grow More Vegetables, as a way of rapidly improving compacted soils.
We are double digging the Kentucky State University high tunnel in an attempt to encourage salts to leach through the soil more rapidly. (Salt build-up can be a problem in high tunnels, where it never rains.)
This two and a half minute video shows about two hours of work.
Updated February 19, 2008