Well the makers of Wikipedia have created the same sort of site, but for racing. It has info on tracks along with guides on what are the best lines to take. It is still young so not every track is fully done or even in there, but I could see it being really useful if your track is on there.
Trackpedia (http://www.trackpedia.com/wiki/index.php?title=Main_Page)

lol... love the sig

its only temporary, I think its too big....thanks ;)