I tried installing my 996 in my 2001 Crown Vic using the double stack way of the ISO technique. There was something in the way so it would not accommodate the regular stereo and scanner.
My son has a Ford F-150, but I don't know which year. He said he could fit both radios in his. I think he may have been trying to talk me out of a radio, though he was unsuccessful.
Whether you take it somewhere to have done, or do it yourself is largely up to your abilities and whether you are confident enough to do it yourself.
If you do it yourself, there are some vehicle specific brackets that you would need for the ISO technique. You can get them on line or a place like Circuit City. The cost is around $25 or so.
You have to do the ISO technique if you want to stack the scanner and regular radio together. The DIN technique only appears to be usable if you don't already have a radio in your vehicle, but I could be wrong.