I have a Zetec in mine, but it's a job, to say the least.
I checked the service manual, and ended up doing the following :
Take the rain shield off the bottom of the car. Take the two bolts out that hold the A/C expansion tank (it's on the driver's side), and move it to the side. This will help in taking the fan out. Then, take the two nuts off that hold the fan into the car, and disconnect the three (or two, if you only have one fan) electrical connections. Then, pull up on the fan housing to release it from the slides. Then, work at moving the housing towards the driver's side of the car so that you can eventually lower the driver's side of the housing, and pull the other side up. It's takes a bit of work to get by all of the hoses and such. Be careful around the top rad hose.
You may also have to take the bolt that holds the A/C hose (IIRC) to the heat shield. Had to do that on mine, but then again, mine is a Zetec, yours a Duratec.
It took me about an hour to get mine out, and about 15 minutes to put the new one back in. Hopefully you'll have similar luck!
Cheers!