Mediation Services serves Southern Alameda County, and is based in Castro Valley. They are a non-profit mediation organization with volunteers who are state certified as mediators. They handle everything from landlord-tenant disputes, quarrels with neighbors, parent-teen problems, and more.
Mediation is a low (or no) cost way to settle your problems with others, without having to turn to either violence or the courts. It is highly effective because the mediators are trained to get to the root of the problem, and help you work out a solution that is fair to everyone. They do charge a small fee for the service, but it can be waived if you can't afford it.
Outside of mediations, Mediation Services also provides training for community members, students, Police Officers, and others. If you're interested in learning how to mediate, they also offer a class. And, they'll be offering an Anger Management class in the near future.