Saxman is correct, except when you do get the Ford harness, you'll need to bypass the Mach 460. I had to do this with my 95, as I didn't the first time, and ended up receiving a new stereo from Clarion because not bypassing it blew out my entire left channel (too many watts returning to the head unit, or something like that?). If you're looking into the hole where the stereo goes, there's a second set of plugs down to the right I believe, in the dash. Those are the ones you have to use. Unfortunately, once I did it, my system then sounded like crap, because there wasn't enough wattage going through the speakers. *sigh* Solving that problem was easy for me though... I put some 12" Phoenix gold subs in the trunk, and wired an amp for the front speakers. Good luck, hope it sounds good!
-Matt