A typical helicopter has cyclic, collective, anti-torque pedals and throttle.
The cyclic is the stick between the pilot's legs and controls the angle of the rotor head. If the pilot pushes the cyclic forward, the rotor disk tilts forward, and the rotor produces a thrust vector in the forward direction, thus the helicopter moves forward. A joystick covers that.
The collective is normally located on the left side of the pilot's seat. It changes the pitch angle of the main rotor blades, therefore the helicopter increases or decreases its total lift derived from the rotor. In level flight this would cause a climb or descent, while with the helicopter pitched forward an increase in total lift would produce an acceleration together with a given amount of ascent. If you have a throttle that can cover that.
The anti-torque pedals, well, counter torque! OK if you have a joystick with yaw, or pedals.
In single-engine helicopters, the throttle control is a motorcycle-style twist grip mounted on the collective control, while dual-engine helicopters have power levers. However turbine engine helicopters (and some piston helicopters) use governors or other electro-mechanical control systems to maintain rotor speed and relieve the pilot of routine responsibility for that task, so the throttle can quite easily be used as the collective.
Much like the SU-37 hammerheard maneouvre (which shows that the engines can continue to run at almost 90 degrees of angle of attack, which would normally cause an engine to flame out) a roll in a helicopter is pretty much useless in combat (and will probably get you killed) but the fact that it CAN roll is an impressive demonstration of the areodynamic, immense power capability and strength of the composite rotors and airframes.
In ArmA, it just looks cool :-)
