There are currently six places to get worms, either through clinical trials if you qualify, or through private companies selling larvae.
Hookworm:
If you have MS, there will soon be a trial in Nottingham, England, using 25 necator americanus larvae, studying the effects for 48 weeks.
http://clinicaltrials.gov/ct2/show/NCT00630383
I don’t know if the Nottingham Crohn’s trial is still recruiting. (Update; trial was completed in June 2009. Contact Paul Fortun to see if any new trials are forming.) It was a double-blind, placebo controlled trial using 10 Necator Americanus larvae, with a minimum requirement of 6 visits over 6 months’ time. You don’t have to live in England to participate. Contact: paul.fortun@nottingham.ac.uk
There was a trial testing hookworms in celiac disease, but it’s completed. If you live in Australia, perhaps contact the trial coordinator to see if future studies are possible. http://clinicaltrials.gov/ct2/show/NCT00671138
To purchase hookworms, there are three companies selling live larvae: (Note: this is not an endorsement. Please do your own research, ask for proof of safety, proof of which organism you are getting, resevoir donor’s blood tests, stool tests, as well as what lab protocol they use and proof that there are no co-infections, and how many organisms you are getting, among other safety precautions.)
http://autoimmunetherapies.com
(www.worm-therapy.com is the same company as autoimmunetherapies.)
TSO
For TSO, or trichuris suis ova (pig whipworm), there is a trial currently recruiting for MS at the University of Wisconsin:
http://clinicaltrials.gov/ct2/show/NCT00645749
To purchase TSO:
Trichuris Trichura (Human whipworm)
Is now available from www.autoimmunetherapies.com
Of course, you could get any of the above from third world countries, but be aware that there are many varieties of worms, and not all of them are therapeutic.