The firm I work for does a lot of ADR. You can take classes in it as part of Hastings' Civil Litigation concentration program, so I am le stoked. I'm definitely interested in the field as I think settlement and negotiation skills are just as important as trial experience, and in many ways even more so since most cases settle (and most parties prefer settlement over a lengthy and pricey trial).
Some ADR companies:
ADR Services: www.adrservices.org
Basically you can hire an arbitrator/mediator which is usually a retired judge. However, experienced litigators w/ a good CV are also eligible (ex. like my managing partner).
JAMS is actually our client as well, and we have defended them in some professional liability cases (One was regarding an arbitrator who apparently knew the counsel for one of the parties. He didn't render any decision, which caused the other party to go bankrupt. So they sued JAMS and our firm was like, "Step up, fools." We lost, took it to appeal, and lost again.