[Off-topic] Dirk:
Mastering the BB Squat is an absolute requirement. Not only for Bodybuilding, but for any sport or fitness training. You're right to be getting started on them. Technique and form is more important with these though than with anything else. There's no place for ego lifting or lazy/sloppy technique. Start light and get it right!

I can't link to any Youtube vids right now as i'm at work. There are some good, multi-part tutorials though if you look for them. I would say, don't use the Smith Machine to squat though. It will lead to injury! Start with a Barbell and stick with it. There are some supplemental exercises you can do, which i'll go into later, but they should be used mainly to help you improve your BB squat, rather than as a replacement for it.

So, you're in the gym. Where do you start? If you have one, the Squat Rack would be a good place! If you've watched your Youtube tutorials you should have some idea what to do. You may have should have practiced the movement without a bar before so now do it in the rack with an empty bar. get used to getting your body under the bar in the correct position before taking the weight off the rests. Feet shoulder width apart, toes slightly out, chest out, head up. Take small steps to clear the rack with the bar resting on your traps, not your neck.

The downwards move isn't started by bending the knees, instead it's by pushing your hips back and out. Keep your torso upright, lower back arched,eyes looking ahead. Bar should stay in line with your body and above the mid foot. Get used to squatting deep. That's ass to ground, beyond parallel! How well you do will depend on how flexible you are. The weaker muscles will let you down and it's those that cause loss of form. That's why we start light and build up. You can't have a weak link in the chain and expect to go heavy with good form and good ROM.

As you get low in the movement your knees will want to come together. Counter that by pushing your knees apart so that they remain lined up over your toes throughout. Pushing back up to standing starts with your heels. That's where the weight should be distributed. If you are pushing with your toes you are probably leaning forward. There's always the fear of falling over backwards but you have to overcome this. If your squat rack has safety bars, use them. And if you do go over backwards a few times, don't worry. We've all done it!

With any luck you're back to standing without any drama. You'll know when you do that perfect Rep as soon as you do it. It just feels right. No wobbling or balancing issues. It's a great feeling! :) Just remember to build up gradually and only lift what you can manage with perfect form and good ROM.

Have a look at the ExRx page:

http://www.exrx.net/WeightExercises/Quadriceps/BBFullSquat.html

Footwear:

No Running Shoes or Trainers with thick, padded soles/gel packs/air cushions etc. You need your feet to be planted. Converse Chuck Taylors or Bare feet. Pick one!

Supplemental Exercises:

Dumbell Squats

Split Squats

Lunges

There are many variations of the above. All good leg exercises. Very useful if you have weak areas and flexibility issues. By all means incorporate them into your routine, but only do them once you've finished squatting! :p

I hope some of that helps mate.