>Does anyone know of a website that lists all the part of the us military? I would like to find out how the army, navy, air force and marines fit together and where all the subunits like the green berets, delta force, the rangers, special ops, navy seals fit in.

On CNN, there was, at least, up to until recently, all the explanations of their specialities, when used, etc. You might want to surf over there.