The Batmobile is the vehicle of choice for millionaire Bruce Wayne, known as Batman in crime-fighting circles. Throughout the comic book series, the car remained pretty much the same, so I shall just talk about the vehicle as it appeared on TV and in film.
TV Series
As tres equis said, the original Batmobile was built by George Barris from a 1955 Lincoln Futura, a concept car. Eddie Graves also assisted in building the car. It cost $30,000 to build the car in 3 weeks. Its value had skyrocketed to $125,000 in 1966. The car had a 390ci V-8 engine, B&M Hydro Automatic transmission, and Firestone tires. In April, 1967, the car went a total refurbishment, including a new engine. George Barris still owns the car, and it is worth over a million dollars.
Batman and Batman Returns
This Batmobile was a drastic step toward a more serious and, well, intimidating version. Anton Furst designed the vehicle and technicians under John Evans built the car in 12 weeks. Bo Welch did the design for Batman Returns when Furst committed suicide in 1991.
Batman Forever
Director Joel Shumacher had a different vision for Batman, and his approach took a more family-friendly view in the atmosphere of the movie. Barbara Ling was responsible for the new Batmobile, a "spiffy" thing with little "wavelets" rolling back over its body. Definitely more kiddy. A professional company named TFX built the car.
Batman and Robin
Once again, Barbara Ling and TFX are responsible for designing and building the Batmobile. This time, the car looks much better, with the annoying "wavelets" gone and a more smooth, sleek feel to the whole thing. The car was made to attain speeds exceeding 200 MPH with its Chevy 380 engine.