I had to replace my shower head and bought a new one. When I went to
install it (screw it onto the shower arm) I realized it was up-turned
instead of down-turned - so shower head could not be used (wrong angle
completely).

The shower arm is "plastered" into the wall so i don't think i can
twist it around. What do I do? try to remove the plaster (or whatever
it is)? Break through it? I dont' want to remove tile or make this
into a major project if avoidable.

That's strange is it in the US? So the one you replaced was articulated
so it would point down? Which you could still do with a chrome 45º and
chrome nipple or a swivel. Is it 1/2 "? If it's a standard set up it
would be a 1/2" riser to a 90" to the chrome arm. If it is that you
should be able to turn it down 180º. If not use the adapter.
Richard

Yes - we're in Los Angeles. The rest of your post gets a little too
technical for me...... the shower head i replaced had two "hinges"
which allowed me to set it up to work (I never thought about it
though).

All those other things you mention - nipple, swivel, riser, adaptor -
where do i get these? Is there somewhere online I can take a look as I
think it will be obvious if they suit?

What/how is the shower arm attached back to the pipe - is it screwed ?
If so can I not just unscrew it and screw it back pointing down or just
get a replacement?

OK Check out this site:
http://images.google.com/imgres?imgu...lr%3D%26sa%3DN
This is a very common installation for a shower. See where the angled
upper shower outlet screws into the 90º that's screwed into the 1X4
support. You might be able to gently turn that 180º clockwise so it is
facing down or CCW but that might leak inside the wall.
Conversely you could add parts onto the outlet pipe. Usually that pipe
is 1/2". Very common. Just go to any hardware store and tell them your
problem. Seems like a 90º or 45º street "el" would solve your
problem.
Richard

Thanks for all your help!