Ok first welcome.
Second, biodiesel and Waste veggie oil are two completely different things.
A couple of questions for you. 1: Are you wanting to make biodiesel at home? This requires no modification to your truck, just a change of the fuel filter when the biodiesel cleans out the fuel tanks of crud. Your injector system on your 7.3 will have no problems with biodiesel, just make sure to have that extra fuel filter handy.
2: Have you had a chance to check out
www.biodieselcommunity.org? Lots of great pages on there to get you started making biodiesel.
I thought about using WVO (waste veggie oil), but when I saw the amount of modifications that I would have to make to my daily driver, I thought it would be better to do all the experimenting on a stationary biodiesel processor.
The Appleseed processor is the most cost effective and efficient way to go if you are just making fuel for yourself. I've been running homebrew here for several months and trucking past the fuel stations without need of a fill up has been wonderful.
I highly recommend biodiesel over WVO, they both have their merits, but with the cooler weather where I live, I came to the conclusion that biodiesel held the lowest risks.
One thing I can really stress to you is to find people in your area who are making biodiesel or have WVO kits on their vehicles. They are a wealth of information and most are more than willing to share their knowledge with you.