you cannot gain muscle without fat, it is not possible, unless you use steriods which clearly you should not. Since you are untrained, it is possible for you to put on muscle without too much fat, but not for long.
In order for you to gain muscle, you must be in calorie surplus. Not all the colories you take in will build muscle, some will be stored as fat. When you are in a calorie deficit, you will, first use glycogen stores, then muscle and lastly fat as energy; you must lose muslce to loose fat. The trick is to try to preserve as much muscle as possible through training and diet.
E.g., Over the last 12 months I've gained about 25lbs. (part of this was muscle rebound). I've gained about 18-20lbs of muscle and about 5-7lbs of fat. I've now been cutting for 3 weeks and will continue to for another 10-15 weeks. In order for me too lose the fat I've put on, I'm going to have to lose muscle. To lose 7lbs of fat, I'm likely going to lose 3-5lbs of muscle. The net amount of muscle I'll keep is in the 13-15lb range; this will be natural gains.
If I continue to train naturally over the next year, I'll be lucky to put on another 5-6lbs of lean mass, doing the exact same thing, get fat, then cut; the goals is to net some lean mass. I don't plan to remain naural as I'm already running below normal T levels.
If you put on 20lbs of lean mass over the next 12 month, 10lbs in 2012, 5 lbs thereafter for 3 years; in 5 years you'll be a ripped 170lb (you'll look like GSP), thing is, you'll probably gain a little fat along the way which should still produce visible abs, so many 175, 180.
Here's the thing though. 2% of guys who start down this jouney actually do it. You should be looking 5 years into the future, not what you'll look like this year, because I promise you that everthing you do will fall short of expectation.