Ok, several semi-sarcastic replies - but that's probably because no one's really sure how to answer the question, as everyone will come across different problems, and it's not really possible to plan for them until they happen.
But I'll have a go at a sensible answer. You'll start off with a trial lesson, which will be very relaxed. The instructor will talk to you on the ground about what the various controls do. Then he'll take off, demonstrate a particular control to you, and then get you to repeat what he's just done. It's extremely easy, and it will stay easy for the next few lessons, too. Over the following hours, you'll continue to get a feeling of how to use each of the main controls, the "secondary" effects of these controls, and start to become comfortable climbing, descending, turning, etc.
After that, you'll move on to stalls. Lots of people worry about stalls, for no reason at all. A simple way of describing a stall is that you slow the plane down enough that the wings can't keep it in the air any more.
(This is actually not accurate - it's not really related to the speed, but actually to the wings' angle of attack - but since I'm trying to give you a feel for what the lessons are like, and not an aerodynamics lesson, it's close enough!) I think that when people here this, they expect the plane to drop out of the sky. But actually, it's nothing like this. The wings are still developing plenty of lift, just not quite enough to balance the weight, so all that happens is the nose of the plane will drop a bit, and you'll start to go down slowly. You'll learn to recognise the symptoms of this before it happens, and how to recover from it safely.
After a while, you'll move on to the only difficult part of flying - circuits and landings. This is the frustrating part, and you will come out of your lessons convinced that you'll never be able to fly. You'll log on to PPRuNe, post in this forum asking for advice, and people will real off the same advice that everyone gave them when they were at this stage. But really, none of the advice helps. The only way to learn to land is to practice - it's just hard to see that when you don't seem to be making any progress. But, one day, you'll suddently discover that you can land! It won't be perfect, or consistent, but most people say that it just "clicks into place". More heartache over the next few lessons, because lack of consistency will mean that you'll still have bad lessons when you bounce all over the runway. But eventually, your instructor will have enough confidence for the biggest moment in your flying career - FIRST SOLO!
The best way to understand what it's like to solo an aircraft is to do it. But, in the mean time, search this forum, and the Wannabes forum, for acconts of people's first solo - this will give you a rough idea of the the emotions, but it won't really come close.
Now, you're practically done. Spend time in the circuit perfecting your landings, then do the cross country navigation stuff (you do all the hard work on the ground, so the flying part is really very simple), a little brushing up, and you're practically ready for the skills test!
Somewhere along the way, you'll have to do some multi-guess type exams - although most of the questions are so easy that guessing really isn't necessary. Your instructor will recommend the textbooks you should use (most instructors recommend Trevor Thom), and all the information is in them - although your school will probably offer ground-school classes if you want or need them, so there's really nothing to worry about.
This isn't intended to be a complete course sylabus, and I'm sure the instructors and examiners who hang around on this forum would be able to pick a million holes in the details. But it should at least give you a rough idea what you've let yourself in for. The main thing to take away from it is that there will be difficult times, especially when you're trying to learn to land, and you should feel free to post here when you come across problems - but don't worry about it. Especially not at first - the first few lessons will be very easy and very relaxed.
The other thing to do, if you have plenty of time on your hands, is take a look at
http://dir.yahoo.com/Recreation/Avia...s_and_Diaries/ This is what I did before I started training (before I found PPRuNe!) and it gave me an excellent idea of what to expect. Many of the journals are American, and there are minor differences in the sylabus, but it still makes excellent reading
Most of all, have fun!
FFF
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