Does any one know if there are kits availible to convert 2x4 to 4x4 or if it's worth the trouble? I have my little chevy work truck that i have invested 7 years in and has treated me right and i would rather modify it than trade it in or by a new one. I should be able to bolt on a transfer case change drive shafts and front axle or am I way off?  

Not entirely sure about the 02 but I don't personally know of any 2 wheel drive that is able to be converted to a 4x4.  Generally the front end of the frame is constructed differently than that of a 4x4.  Such a conversion would most likely require a complete donor rolling chassis.  At that point considering time and money invested in moving everything you would be much better off trading or buying an additional complete vehicle.