No, the F-250 mirrors will not fit on the F-150. If you want tow mirrors, call up Dominc at Tasca Ford, 800-915-3141, and order up a set of the 08 F-150 towing mirrors w/power, heat and puddle lamps. As Spooner said, they are around $300 for both and they bolt right in. Check out this thread this is what I referenced when I got them for my truck, the thread was nowhere near that long at the time though. It has some good info in the first few pages that should help.
Telescoping trailer towing mirrors finally on