go to your auto parts store, buy fork "keys" (ford radio removal tools), not more than $5.00. Stick the keys into the holes slowly till they click, press outward on each and pull out. the radio should come out with the keys.
Id highly reccomend that you buy a haynes manual for refrence. it will tell you how to dissasemble this stuff.
I have the keys and couldn't get the radio out of my '04 and tried using "other" objects in my '01 wagon when I had it and neither simply pulled right out. I haven't had a chance to look into it on my car as to why it won't come out but I'll figure it out.
Here are a couple of pics that may help. This is the side of the radio unit, installed in the dash piece (the dash piece is out of the car obviously). The radio is face down. The top of the radio unit is on the left side of the pic. That black metal clip is the thing that's holding the radio in.
I have also had good luck using allen wrenches, instead of keys. Really, anything will work if it's the right diameter andf long enough. You want something that just barely fits into the hole. Coathangers don't work all too well, because they are too small in diameter. If you put a few small kinks in it, and play around you'll probably get a hanger to work though.