Re: ...

Yes, wildspace, the flow, and terrestial worlds are all part of the prime
material plane.  Conected to the Prime material plane are the Astral and
Ethereal Plane (this is true everywhere except the phlogiston) The astral
plane is conected to the Outer planes via color pools, and The Ethereal Plane
is connected to the Inner Planes via Ethereal Curtains.  If you have any more
questions, please e-mail me personally at Hcarth@???.com, this in case some
readers don't care about the Planescape setting, after all this is the
Spelljammer listserv.
                                           --Hcarth