One of the main stumbling block in the exploring of altered state of consciousness is mental chatter. There is also falling asleep is a lesser problem, often when people fall asleep during their meditation it was an indication that they lack sleep at night once this is addressed that wont be a problem anymore. If you are new to working with Binaural beat CD then you might fall asleep during the first sessions but it will vanish when you get used.
There are many methods to reduce or even stop mental chat. I read that some students of the SilvaMind course uses a method whereby they talk to someone in the room while they enter in trance, they described their perception to a listener, it helps to stay focused and it also helps with the brain hemispheric synchronization, doing the talking and doing the deep relaxation has some beneficial effect. This technique is also known as image streaming. If you do not have someone to talk to; you can use a digital recorder (voice activated).
To recap the technique help to reach theta and focus your attention on what you are doing.

Klaus Joehle in his book The messenger explains his technique to deal with mental chat.
From the book “First you get yourself all relaxed and calm, then just for a minute visualize that there is a beam of light coming from your soul and going right down from the top of your head, filling the whole area with very bright light. Don’t keep on visualizing this, just keep it in the back of your mind. It’s like if a carpenter was on your roof repairing it, you don’t need to stand there and watch him all day, you just know that he is there. So in not so many words, you just leave the light there without constantly focusing on it. That will keep the whole area very busy. I don’t know exactly what this area of the brain is supposed to do, but I know this works and that’s all that really matters at this point.”
I tried Klaus technique without much result, it caused me even more thoughts to creep in. But, may be, you can give it a try.

Robert Bruce author of Astral Dynamic advocates strict mental discipline through concentration exercises, this is also what recommend Dr George King. I choose this route after one or two months of concentration exercises it is a lot easier to deal with mental chatter.
What I do when thoughts coming in I lightly put my focus away from them, they tend to stay like cloud in the sky then evaporates. This does work when you have been trained with some concentration exercises.

They are other methods involving breathing patterns and mantras, I’m less familiar with these methods.

A list of related entries:

Deep trance state

Immrama Insight Tranquil Ocean Waves CD! First impression !

Tough Love is OK

Advices for deep trance meditations

Meditation matters

Meditation Therapy for Stress and Change with Jyotish Novak

drinking enough water

Progressive Relaxation