For information on NASCAR's three major divisions (Nextel Cup, Busch Series, and Craftsman Truck Series), the unquestioned authority is racing-reference.info. While NASCAR's official homepage only contains results going back to 1975, this site contains complete results going all the way back to 1949, when the premier division was known as Strictly Stock. (It became Grand National the following year, and Winston Cup in 1972, before becoming known by its current name in 2004.) It also contains a searchable database including every driver who has competed in any of the three major divisions.
For other stock car racing, check out the Stock Car Results Archive and its associated forum (registration required and well worth it.) The owner's main interest is in the history of the ARCA series, but there is a fair amount of information about other series as well (the NASCAR Dash series, ASA, and IMCA stock cars, for example.)
For Indianapolis-type racing history, I recommend champcarstats.com. Here you will find complete coverage of every race in the history of the Indy Racing League and Champ Car World Series, as well as Champ Car's predecessors CART, USAC, and AAA. Also included is the history of the Indy Lights developmental series (which ran from 1986 through 2001) and the Indy Pro Series (since 2002). The history of the North American Formula Atlantic series is currently under development. Also, as a real bonus, this site contains the only detailed information I have ever found on NASCAR's Speedway division, which operated for two years in the early 50s with "Indy" cars instead of stock cars. (The results are quite detailed for 1952, but rather sparse for 1953.)
For sports car racing history, World Sports Racing Prototypes has done an incredibly detailed and thorough job of chronicling the many sports car races, not only in America, but throughout the entire world.
Several sites are dedicated to the history of Formula One racing. I am partial to The Formula One Archives, which also covers several races conducted under Formula One regulations which did not count towards the World Championship.
For American short-track open wheel racing, Open Wheel Times is an invaluable source of information, containing results from many local sprint and midget shows, as well as results from defunct sanctioning bodies.
For fans of New England area short track racing, YankeeRacer.com features results from several of the area's local tracks, featuring those at Seekonk, Stafford Springs, Thompson, and Waterford. Also, Northeast Racing Stats Central features results and other statistics from several of the area's touring divisions, as well as the Airborne Speedway, Catamount Stadium and Thunder Road tracks.
A new page dedicated to short track stock car racing history can be found at Short Track History.
For results of races at the Kansas State Fairgrounds from 1909 through 1957 (and still being added to), see Bob Lawrence's page at http://winfield.50megs.com/Hutch_Nationals/Fair/Feature_Winners.htm. Lots of great IMCA Stock Car and Sprint Car results, among others.
Last updated May 5, 2008