What You Should Know Before You Start
Helicopters are arguably the single most challenging R/C models to build and operate. They're mechanically complex. They require you to master two distinctly different skills, forward flight and hovering. And to pilot them successfully, your FULL attention is required at all times.
This said, manufacturers have made some very impressive advances which give more hobbyists a good shot at getting a heli in the air and keeping it there. The Raptor would be my personal choice, It is easy to construct and repair, and they are very reasonably priced, they are also becoming a very popular choice with Club members.

What Can an R/C Helicopter Do?
Pop down to your nearest club and you will probably see some things you thought were impossible. They'll hover in one spot, fly backwards, sideways, they can pirouette, perform stall turns, loops, rolls, standing loops and rolls (a loop or roll with no forward speed)... even fly upside-down and hover while only inches off the ground. Let's see full-size helicopter do that!
In normal forward flight, an R/C helicopter flies at about 40-50 mph and approximately 100 to 300 feet high. The current world record was set by Dave Whitney of the United Kingdom who achieved a flight speed of 87mph in 1986. Dana Swah of the United States presently holds the altitude record of 6,022 feet.

First steps (Visit your local club)
I would firstly recommend you visit a local Helicopter club. To find your nearest one visit the BMFA Website of which the EMHC is affiliated, and I am sure you will find one within a reasonable distance. When you find your local club, make a visit and speak to the members, you will almost certainly get some good advice about how to start, where to buy parts, which is the best helicopter for beginners, and most importantly you will see them fly.
After your visit to your local club, you should have gained some detailed information as to the quality and whereabouts of your local Heli shop, and you will probably know what helicopter you are going for. Visit any shops that were recommended and see what they have to offer. Don't be affraid of getting all the information and going back to the club for further advice before parting with your hard earned cash. Club members will have a better idea of which items will last and which won't. When you have parted with your cash and you have bought your Helicopter invest in the club membership, this will almost 100% save you money and is a fraction of the cost of buying your heli. Remember the club members who gave you good advice will hopefully check over your helicopter and help you get it off the ground safely.

The Helicopter
When choosing your first helicopter you first have to decide which type of Helicopter you wish to purchase. You can purchase a collective pitch machine, or a non-collective pitch machine. I would strongly suggest the collective pitch machine. Although it is a bit more expensive initially, it is by far the more versatile and will help you enjoy more advanced stages of the hobby after you have learned to fly. You will also find the learning process easier with a collective pitch machine.
Unlike aircraft where there are specific trainer models geared solely for the first time kit, the differences between helicopters is more suttle with the major difference being size and precision. The larger and more precision a machine is, the better it will fly. These machines would make great training helicopters but they are usually a lot more expensive, with high precision parts, and would be very costly to repair in the case of a crash. They are better suited toward competition and the experienced modeler where accidents are usually minimal. Keep in mind, when learning to fly a helicopter you are bound to have a crash or two and parts are going to have to be replaced. Replacing parts on a precision machine could really run you a bill! A good place to start would be a machine designed for a .30 size engine, a stable flyer with collective pitch, and one with a good avialability of parts.

The Engine
The helicopter engine is similar to most other 2-stroke glow engines except that it has a larger heat sink head for better cooling, and a carburettor with improved mid-range adjustment. When purchasing the helicopter engine, the muffler is not included. Your local club will almost certainly have limits on noise levels and some advice on known good setups from club members prior to purchase will ensure you will not need to upgrade.
There are various different starting methods. Some come with a pull start system for very simple starting. Others use a cone start where an electric starter is used in a manner similar to starting an aircraft. Others use an electric starter and a belt for starting, but these are not common these days.

Radio Transmitter
To me this is probably the most important item. My advice would be to buy the best Transmitter you can afford at least a Futaba field force 8 or equivalent. I learned the hard way and bought a cheaper model to suit my budget, but soon found that I needed more advanced features which were only avaliable on the better quality radios. My second radio was a Futaba PCM1024Z which has all the features I could possibly need. Now I have a redundant radio which no one would want due to its limited features. I have yet to find something I need to do and can't with my PCM1024Z. Also if you find you do not want to continue in the hobby it is much easier to sell a good quality radio as opposed to one of the cheaper models.
Transmitters are usually bundled with Servos, Reciever, Battery. But my advice would be to buy all these items seperate as you can choose the better types of each component to suit your needs. Details on other radio equipment required follows.

Servos
Standard servos are adequate for the beginner, and are cheap enough to dispose of if you need to buy better quality ones later. The more you pay the better the servo. Good servos have bearings as opposed to bushings, Good servos have metal gears as opposed to plastic, They also have higher torque and greater speed and better motors. Digital servos are also avaliable. As you can see it can get confusing to the beginner. So for learning stick to basic servos.

Reciever
Two basic types are avaliable PPM and PCM. I would recommend for beginners the PPM unit, it is cheaper and is a tried and trusted technology. As you progress into the hobby you may find that you require the advanced features of the PCM unit.

Gyro
There are two basic types of gyro mechanical and Piezo. The mechnical gyro is very rapidly becoming extinct due to the new features and presice control obtained from the Piezo Gyro. I would recommend a heading hold Gyro CSM or similar type.

Tools
To build your helicopter kit you will need proprer tools. Always use the correct size screwdriver, spanner or allen key for the job, quality build should be your aim at all times. Don't rush construcion and always use threadlock where advised. As you progress into the hobby buy tools as you need them and they will soon build up.

Construction
After you have bought your helicopter, and assosiated equipment, you will be itching to get started. Please resist the temptation to build it immediatly. READ the instructions a couple of times, and get familiar with all the parts in the box, and check nothing is missing. Once you have started you may be looking for hours for something that was never supplied (experience talking here).

All kits will have a sequence of jobs to complete, this is done this way for a reason so do the steps exactly as instructed, and you should not be dissapointed with the results. Always work in a clean environment. Wait untill you can get a nice clean table with no distractions. You would be surprised how much quicker this makes it go together.

Installation of Radio Gear
Once you have built you nice new helicopter you will need to install the radio equipment. Any defects or ommisions here will certainly cause a crash. Ensure that you protect all installed equipment from vibration using proper servo mounting bushes, Gyro mounting pads, and I would suggest fitting your reciever in a well designed crash protection box. Fit the largest size battery pack you can get for your helicopter. Make sure all wiring is neatley routed through your helicopter and protect it from rubbing on framework where nesseccary. Any extension servo leads used tie the plug and socket together to avoid seperation during flight, clips are avaliable from model shops for this purpose.

Starting Equipment
Before you can fly your helicopter you will need some Fuel, Fuel Pump, Starting Motor, Glow Stick.

First Flights
Once you have built your helicopter I would strongly advise you to join a club, take your newly built helicopter to your flying site and ask an experienced flier to assist in the setup procedure. It will be better to let an experienced flyer take the first flight.