The temperature gauge started to rise one day while driving, so I
pulled the car over immediately and turned off the engine.  I checked
the coolant reservoir (assuming I was low on coolant) only to find
that there was plenty.  I waited a little while, started the car again
and drove home with the temp gauge in the normal range.

 Once home, I noticed dripping coolant below the car halfway between
the passenger and driver side.  Once under the car, I notice that the
majority of the fluid was coming from somewhere between the engine and
the firewall (as opposed to near the radiator).  I also noticed that
if I park the car on a downward slope (the engine below the trunk) no
colant puddle forms.  However, when I park the car on an upward slope
(the engine above the trunk) a very large puddle forms.  Also when I
squeeze the upper radiator hose and listen carefully (with the engine
off), I hear air sucking in and out somewhere between the back of the
engine and the firewall.  I cant seem to trace where the leak is
coming from while beneath the car, nor can I see what is sucking air
in and out when I squeeze the upper radaitor hose from above.

 I know the general area that the coolant is coming from, I just cant
seem to locate exactly where it is.  Any guess as to what could be
leaking coolant between the back of the engine and the firewall?