Jimm 8/4/2012First step - the a/c system must be fully charged with refrigerant. Next - start and run the engine with the a/c system operating. Using one of these tools; a/c system dye, a/c leak detector - trace each of the a/c fittings - at the major components; compressor, condensor, evaporator - and each hose fitting - look for dye evidence and scan with the a/c leak detector.
The actual repair will vary - depending on which component may be leaking or at fault. Try the 'How-To-Guides' feature on the AutoMD website for more specific steps - including photos.