How do you locate a leak in the a/c system? I have a 96 explorer and ac till now worked great but it lost a charge I recharged in and now 24 hours later its empty again . No signs of a oil leak or dye leak anywhere that I can see and I think it should show up?Any Ideas?

A 24hr leak out would be a large leak. Possible to see with a trained eye, however, I use high dollar equipment such as a sniffer and it will pin point a leak in no time at that rate.
Most of the time, in like you describe, a rock hits the condenser and makes a small puncture.

Cnsidering the age of the vehicle, it could be compressor hoses, but a 24 hour leak is a big one and the rock sounds more plausible.

Leak detector, not really high dollar.

Robinair 16600 Leak Detector - Air Conditioning (http://www.tooldiscounter.com/ItemDisplay.cfm?lookup=ROB16600&source=froogle&kw=ROB16600)

Did you add dye? UV or visible?

It could also be the evaporator inside due to leaves and water. You stick the leak detector in the drain of the AC or the air vents inside.

LOL yeah right! Tell that to my Snap-on man. I hear you, though. They can be had for cheap.