Well...how well your diesle runs on vegoil depends on several things. In climates where vegoil can get thick..or in my case (MN) solidify a bit of conversion is required...but in tropical climates some diesels will actually start when "cold" on strait vegoil...but lack power unless the oil is thinned by mixing diesel fuel or warming with a fuel heater (either coolant heated or 12vdc). And some problems with upper ring land coking may be experienced eventually if the vegoil visosity is not lowered.
Not as simple as just pouring in vegoil and going..but not very difficult either.
A good forum with friendly participants (much like this one) for finding out more on the subject is at:
http://biodiesel.infopop.cc/6/ubb.x?a=frm&s=447609751&f=159605551
My netfirms site also has a FAQ page for those that don;t want to wade through tons of posts (though the inopop forums archives are pretty simple to search) for answers to basic questions.