This subject has come up quite a bit over on ford-trucks.

Pretty much any diesel made after 1996 uses all vitron seals/hoses which are 100% compatible with Bio-Diesel. If you have a 99+ Powerstroke your good to go!!

Keep in mind, Bio-D is a solvent, you WILL plug a couple of fuel filters until all teh crap is cleaned out of your tank. Also, Bio-D has a higher Gelpoint. If you see freezing temps in your area, be prepared to add some form of anti-gelling additive.

You can mix Bio-D with regular D with no problems.

If you can buy Bio-D for less than regular D, then DO IT! Expect a slight loss of power and MPG as Bio-D has a slightly lower BTU content as compared to regular D.

Someone made a comment about getting 26mpg out of a powerstroke. I have YET to see ANYONE get that kinda mileage without driving like a grandpa, and running empty with great tail winds.