Try checking your power steering fluid reservoir to see if it is low, as it is common for the power steering fluid cooler to start leaking on older models, I have had to change mine. It will be at the very front of all the radiators and be at the bottom. It is shaped like a U on its side with cooling fins along the top side. It will start dripping at first (or it could be the rubber hoses to the cooler ) but get worse gradually.
Take off the shroud under the radiators ( usually 5 bolts in the middle and 2 under the wheel arches ) and then look up under the radiators to see what is leaking.
If it is the power steering cooler or its entry hoses you can buy these from Ford for about £50 (and they come with the joining hoses and clips attached) BUT - it is a real pig to get to the fixing bolts as they are directly in front of the air Con rad with very little room to work. I had to unbolt the lower rad mountings and push the Rads (water and A/C) right back to get to the cooler bolts.
If the power steering cooler is not leaking then it is likely to be the Auto Transmission Fluid cooler pipes that are leaking, These I believe are attached to the main radiator.
Hope this helps.
Steve J
August 2007