It's not new by any means at this point but Truth in 24 has got to be near the top of the list of racing movies. I just noticed it on my DVR and watched it for the first time in a year or so.
Basically a documentary of the 2008 Audi campaign for the 24 Hours of Le Mans. I'm a big Le Mans fan so naturally I think it's the greatest thing ever but no matter what kind of racing you like it's hard not to enjoy it.
Available on iTunes for free as a HD download.
iTunes Store