For all you want to know about TSO, go to www.ovamed.org. Note that this is dot org, not dot com. This site has information on the hygiene hypothesis, the theory and mechanism of action of TSO and the published studies on the use of TSO in the treament of Crohn’s Disease and Ulcerative Colitis. You can also order TSO online.
This article about Dr. Weinstock gives a brief outline of helminth therapy
This is the abstract of the published article by Summers et al on the randomized controlled trial of TSO to treat ulcerative colitis
For a very good overview of the science behind helminthic therapy, see http://autoimmunetherapies.com/science.html
Another excellent, non-technical explanation of helminths and the hygiene hypothesis by Dr. Joel Weinstock