Would a low carb, high protein, high good fat diet be good for a beginner?
If you ask if the diet would be effective for a beguiner the answer is yes, i would sugest you read the crum post on that subject.
(The Ultimate Diet to Get Ripped while Maintaing Muscle)
http://boards.elitefitness.com/forum/showthread.php?threadid=124559
If the question is if the diet is the best for a beguinner the answer is probably diverges, usually this type of diet is used by already thin people who are trying to achive very low bf %, i would say it isn't the best. But it still works for others with higher BF%. I can tell you it is not an easy diet to do and that also results may be different for different persons. Give it a try.
The advice i would give is that you gradually take out carbs from your current diet, to give time for the body to adapt to low carbs.
I would sugest you read this post by vageta: "The "Not so low" low-carb diet."
http://boards.elitefitness.com/forum/showthread.php?threadid=135467&highlight=better+preworkout+meal
It has very good info and it is still a low carb diet, you could start from there and then go to a lower carb diet if you feel like.
How many carbs would be in that carb meal, or on that day?
the time and amount of carbs to eat depends of some factors like your body weight, when you train, the way you react to them (read vageta post on that matter).
I don't know enough about reffeding in low carb diets to give you a good answer, i sugest you take a look at Par Deus articles about leptin.
I've heard about people losing bodyfat, and gaining a good amount of muscle while on these types of diet......
I'm not so sure about that, usually dieting time is not the time you will gain a lot of muscle, people try to lose the less muscle they can on diets. But it isn't impossible and i would say that the quicker you want to lose weight the more probability you have of losing some muscle. Anyway and mostly for a beguiner and talking on my own experience when i started dieting i started to eat better, at better times and eating a lot more protein than i use too, so this as a positive efect in gaining muscle.
Everyone is different, give it a try and see how you react to it.
Good luck.