MOTM

> Quick question.  Is is possible to power an Op-amp with Ground on the +V
and
> the usual negative voltage on the -V ?

Yes. But the rest of your circuit gets more complex then. Instead of
refering
your signal to GND, you have to "lift" it to something between +V and GND.
A lot of extra capacitors and resistors needed if it's a big circuit - not
really recommended.
For a small circuit (guitar FX stomp boxes!) it makes sense, because you
only need one power supply / battery.

JH.