"scubajenn81, how long does it usually take for muscles to develope on the body? Like I want to have a six pack or something? I've been doing it for about 5 months now..."
Increased muscle size comes from the increase of size of the muscle fiber more then the actual increase of muscle cells.
When you start a heavy resistance training program, changes in the types of muscle proteins start to take place within the first few workouts. As you continue training(3-4 weeks),the amount of muscle contracting proteins increase making you able to lift heavier amounts of weight (According to the National Strength and Conditioning Assosiation)
In real terms, in order to effectivly stimulate the growth of muscle, you have to stimulate it enough to really tire it out. It is better to do that though full body exercises like squats verus a leg extension on a machine (provided that you do it correctly that is). It is more functional and you get more muscle recuitment.
When you max out a muscle, your body will build it up again making it stronger and stronger. However it will take time, you can safely lose up to 2 pounds per week, but it takes more like a month to put on a few pounds of lean muscle.
When it comes to abs, you want to be sure that you are training the entire core area (abs and back), not one section, and be sure you have a healthy diet. You can do all the crunches you want but if you have a beer belly, you will never see the muscle structure underneath. In addition, you would want to be doing some cardio to strenghen your aerobic systems and help with your breathing during a dive. This will also of course add to any calorie burn that come along with the reisitance training.
If you have been working out well for the past 5 months, you should be seeing and feeling some gains, if not, it does not seem to me that you are working out hard enough, or other activies in your life are balancing out any real progress. That said, you are not going to be a body builder in 5 months (unless that is all you do 15 hours a day), but you should be going up in weight that you are able to lift and do more cardio then you were able to do.
If you are really interested in your lean muscle gain, ask a local gym if they have any ways to measure your body composition. The best way is though water submersion, but that can be pretty costly. Most gyms will have a set of calipers, or at the very least a electronic way to calculate it (NIR). Either way, have someone that knows what they are doing, do it and record your results. Then check it every 6-8 weeks. Be sure to go at the same time of day and avoid exercise and limit caffeine before the measurements. It is also reccomended that you change your exercise routine that often as well so your body does not have time to adapt to the workouts you are currently doing.
Anything else?