I have a 1995 Civic with a 1.5L motor. The car has been overheating and I replaced the thermostat, but it still overheats. I then pulled off the hose leading to the thermostat housing to see if there was coolant flowing and it is not. I'm figuring that I need to replace the water pump. I am wondering how difficult a job it will be to replace the water pump and if it has to be accessed from under the car. Any help would be appreciated. Thanks.

Not difficult at all... get a haynes' manual from the local parts store w/ the water pump, it's only about 10 bolts... you should also get a timing belt kit while you're in there, since you have to remove the timing belt to change the water pump (that's what drives it)

Remove the crank pulley, (one big bolt, 19 or 21mm)
remove the upper and lower timing covers (several 10mm bolts, I think 7)
loosen the timing belt tensioner bolt (13 or 14mm)
remove the timing belt fully (you will need to remove the front engine mount and let it hang slightly to do this)(17mm for actual body to mount bolt, 17 or 19mm for two bolts that hold the mount to the engine)
replace the water pump (you'll know right off when you see it)(probably 10 bolts, 10mm each)
set crank to TDC and cam to TDC (note alignment marks)
Install new timing belt (replace front engine mount afterward)
turn engine one full turn counterclockwise (check alignment of TDC marks on both cam and crank.)
tighten tensioner bolt (12 or 14mm)
Check belt deflection (should be no more than 1/4 inch @ 30 in.lbs) -- basically, wiggle it.. you'll know when it's tight enough. should just be a lil tighter than a alternator belt.
reinstall upper and lower timing covers
Reinstall crank pulley and alternator/ Air conditioner / power steering belts (as equipped)

Voila! you're done, and you should allow the engine to warm up before driving it, to "set" the gasket, otherwise, you might put more pressure than it can hold before it hardens, and it will leak... causing you to have to go through all that again.

You CAN get away w/o changing the timing belt, but you still need to reset the timing after changing the water pump... and the life of your engine is at risk if you don't change it, so I wouldn't cheap out here.

I was doing some more checking to find out for sure it was the water pump. I pulled the thermostat back out and still now coolant flow. I then pulled the upper radiator hose off and again, still no coolant flow. Is there anything else it could be besides the water pump. Thanks.

there isn't really much reason that it would stop flowing, other than a plug in the coolant lines..