This is an old project from 2000, so please excuse the low res pictures. This is a hydro setup similar to my recirculating hydroponics with the exception that it uses an air pump instead of a water pump.
Step 1: parts
a pair of buckets, check you local grocer's bakery, they'll often have them for free or a buck.
an air pump
a piece of pex tube 3/8ths
1/4 inch irrigation connector