Officially (or unofficially), RC helicopters are DEAD as we know it but quadrocopters are become ever more popular. For those of you who’s thinking about building yourself one, you might want to take a look at this particular setup using Arduino and Wii Motion Plus.
The project uses Wii Motion Plus coupled with I2C communication to Arduino unit to make use of the gyroscopes inside and also save a bunch of money on the setup.