The September New Mobility has an excellent article on ADA suits (Small Claims, Big Victory). Unfortunately the text isn’t available online, but the opening paragraph explains what so many people do not understand:
Most people are aware that the Americans with Disabilities Act gives people with disabilities some rights, but that’s about where the general understanding ends. Even less clear is how an individual can assert his or her rights under the ADA and compel a business to comply with the law. Some people think the police can enforce the ADA or that there is a specific federal enforcement bureau. Not so. ADA violations are enforced through civil lawsuits by private individuals like you and me. Although the Department of Justice does bring lawsuits occasionally, chances of them taking on your local video store with three steps and no ramp are remote.