Title II covers public services or what is better known as state and local government. The federal government is covered by another law, the Rehabilitation Act of 1973. The requirements are the same, but the law is different. Title II says that state and local governments may not discriminate against people with disabilities and must provide what's called full program access to people with disabilities. Title III covers public accommodations.
Public accommodations are any place or business that affects commerce.
They may not discriminate against people with disabilities in providing their goods and services. Title IV is the telecommunications provision, which established relay services throughout the entire country and talks about requirements for captioning. Title V are the miscellaneous provisions which you never hear about, but which are important. This title talks about how the ADA relates to other disability laws and basically says that whatever law provides the most protection for people with disabilities has precedence. The ADA covers people with disabilities.