It's a common misconception that if you are gaining or maintaining at the beginning of a diet/exercise regimen, it's because you're "gaining muscle and losing fat." True, you are gaining strength, but the weight is usually water. When you stress your body with exercise, it starts to store more fuel in its muscle cells so it can easily power your workouts. The process of storing glucose for fuel and converting it into ATP for energy uses a lot of water, and so your muscles store this as well. This is why though you've lost an inch off your belly, the scale still reads the same. Don't fear that you'll be forever bloated or rush off to buy some OTC diuretics, the extra water retention will stop once your body has adjusted to the increased activity load. You ARE losing fat at this time, and gaining strength and efficient fueling in your muscle cells. It just takes longer for the scale to notice than your waistband.
Furthermore on the topic of muscle gain:
Strength gains can be seen almost immediately after starting training. This happens because your muscles are getting "smarter," that is to say that the connections between your brain and muscles become faster and more effective, so that a greater number of muscle fibers activate to perform an exercise. Only when your nervous system has reached its max activation potential, and you continue to progressively challenge your body, will your muscles "grow", or hypertrophy, to meet the demands you put on them. This process usually takes 4-8 weeks to kick in, depending on your training, age, diet, and genetics.
So don't be afraid that hitting the weights will hold you back in your weight loss! Increasing your muscle activation and density will actually raise your metabolism and energy, giving you a boost of fat-burning power!