In article .com>, " > wrote:

>gtplanet.net will tell you everything you want to know about GT4.
>Including cars, tracks, along with how and where to win (unlock) them.

Or gamefaqs.com

I think you have to just play x number of days in GT mode. Every
14th day (1, 15, 29 ...) you unlock another track. Sorry, but at
least in the US version, Le Mans is one of the last. So something
like day 280? All is not lost, you can cover a day by just
watching a race, or buying/selling a car, or getting an oil
change(?).