B.H.
My son who is 5 and a kindergartener has a headstart classroom within the same school he attends. The only difference that I see in a headstart class and other preschool programs is that one is free and the other is not (headstart being free).
They teach those children in headstart the same things that they teach the kids in a regular private program where parents are paying $300 plus a month. The only thing is that to get enrolled in a headstart program you must first have certain risk factors (like a developmental delay or be low income). However, it depends on what type of funding the program gets because some headstart programs can take a certain number of kids who are not low income or don't have a developmental delay. My 4 year old son was accepted by two different schools and he does not have a delay nor are we low income(we are not what headstart considers low-income) . So we were very surprised to get in.
Don't be fooled that this is not a good program. Many parents try to get their kids in. If the program is located within the public school those children participate in many of the same field trips, school activities and gym classes as the kindergartners.