tdskip:
BobbyD has given you a good list. In addition to his and other suggestions you could change rear brake drums to alum, or better still go to the disc conversion, rear coil over shocks conversion, alum flywheel, the front brake system could be replaced with lighter rotors and calipers, get a SS header to replace the stock cast iron, a single SS big dia. exhaust system, take the convertible top and trash it (fair weather driving only), replace the windshield with that little racing thing, replace the stock motor with a 200 plus HP GM or Ford 4 cylinder alum block/head motor, strip the paint and run primer only, and last get rid of the wife and you don't need the passenger seat. There, done.
Some serious suggestions in there somewhere. It really depends on how light you want to be and how much you want to spend.