There isn't a tutorial that I know of, or if there is it's not very helpful. I've recently done a mod for my personal use and it works quite well so I, and I'm sure many others here, can help you if you have questions. The best thing to do is start by getting Tony's 2009 Empty mod (http://www.gp4db.com/download.php?file=files/mods/2009/2009%20Empty%20Mod%20(Tony).rar) and work from there. I just worked it all out as I went along, it's surprisingly simple when you get into it.
EDIT: Maybe I should sit down tonight and start writing one based on my experience with it, just to help the others out.
Edited 1 time(s). Last edit at 06/27/2011 03:40PM by Bruce D.