You need:
Dash kit , factory to aftermarket wire harness, and the Antenna adapter- Best Buy or most any local audio shop will have this. Just tell them what kind of car, and DEFINATLY CHECK the parts. Sometimes they do give the wrong one.........just an after thought of the case in Best Buy matters....
If you have no tools:
A Ford factory removal key, or a bent coat hanger will do the trick. Look at the removal key to get the idea of how to bend the hanger. The "key" will slide into the 4 small round slots which relese the entire headunit. A set of wire strippers, and or crimp pliers. Find the yellow or red handled kit at Wal-Mart, 9.00, has everything you need. Also get an extra pack of wire crimp's and a roll of black electrical tape. You can never go wrong with wrapping the new spliced wires for added protection, since you may have not installed too many headunits before......thats about it- there are other things that you need if installing amp, or new speakers, but thats the basic installation list of parts.