If you car has press-on gears (which I am thinking the '99 and '00 do have them), then you will need a set of new cam gears. You will also need new cam bolts from the dealer if the new cams do not come with them as they are one-time use bolts.
If you have bolt on gears, you will just need new bolts and front cover gaskets if you change the cams the "traditional" way. You also have the option of using the Anderson Ford Motorsport cam-change tool and you don't have to remove the front cover. That is how I changed my cams in my '03.