Are you referring to LPG conversion or to propane fumigation? If it is the former, there are a number of companies that have undertaken this with good success. For the latter, there is very limited information available. I have been unable to locate a "kit". I do recall finding a website that described in great detail how someone had assmbled a system that trickled propane into the air intake. Suprisingly, propane has a much higher flash point than does diesel. However, once ignited it burns much faster and it acts as an accelerant to ensure that all the diesel is burned (this is partly where the extra power comes from). In theory, you can gain up to 40% more power by increasing the amount of propane. This would probably be a temporary increase and would only last until the engine tears itself apart though.
All of this is "net knowledge" and I haven't done it myself as I can't afford to experiment with my daily driver.