Is OpenGl-ES "just" a specification, or is it
also libaries that run on "ARM" and other
It is a specification, but manufacturers have early sample implementations or are working on them. Ti for example has an OpenGL ES workalike library that runs on their OMAP processor utilizing both the ARM and the DSP. I dunno how functional it is w.r.t. spec compliance but it draws 3D stuff. I assume that would be available to anyone who uses those chips.
Right now OpenGL ES cannot be formally released by a manufacturer AFAIK because it has not yet been ratified (?), but there's enough information out there for them to get working on their implementations and some have unreleased libraries today.