The Codemasters Forum has news that the playable demo for Colin McRae DiRT 2 will be released tomorrow at 2:00 pm GMT, which is 10:00 am EST (thanks Derek). Codemasters also explains a prerelease demo for the rally racing sequel was leaked over the weekend, but they advise against playing it:

We will be releasing the Official DiRT 2 Demo Tomorrow (1st Dec) at 2pm GMT

Over the weekend a leaked early version of the DiRT 2 demo has appeared on the net on various download sites. I would advise people not to download this unsupported version of the demo as it is not the final version and will not give you the best experience of the game.

As I mentioned previously this is a work in progress version of the demo which was not intended for release.

Once again I would advise people not to download the leaked version of the Demo and hold out until tomorrow and experience DiRT 2 the way we wanted you to.