I've been doing p90x for about four months now on almost a daily basis. I've noticed my pattern of eating has become more frequent and I supplement with protein every day that I work out. However, I'm not getting the results I expected to get from having done p90x for this long. I can curl on average about 5pounds more than I used to, I can do a single chin-up, and all together i've lost about 5pounds of fat. I'm not sure what else I can to boost my results. Ideally I'd like to be 180lbs (I'm 6'1"), curl 35's - 40's, be able to knock out a set of pull-ups, and just look a little more trimmed. Is there anything else I should add to my regiment?
Measure progress and eat right
It's good that you know your goals, and are able to stick with a workout program -- those are both huge benefits that will get you far. I'd suggest starting from them, as a matter of fact!
So you know that you'd like to have a stronger upper-body (more pull-ups and curl weight, i.e. back and arm strength), and -- I assume since you mentioned losing fat -- be a bit more trim. That's awesome. Based on those goals, the best things you could be doing are:
a) eating right -- this is the best way to trim up, period
b) doing exercises that will strengthen your upper-body, like the pull-ups and curls you're doing, and aim to increase your reps and/or weight gradually; and
c) add some cardio to your daily routine, to help you gain muscle overall and become more fit, plus firm/trim up a bit further due to good muscle tone.
Now, P90X (which I did for a while too) includes the cardio and upper-body work. It doesn't include eating right -- in fact, for the ~500 calories it burns, it adds a protein supplement that can run just about the same amount, depending on how you take it, resulting in little or no weight-loss. Also, the extra-fast sets of pull-ups may not be what you need (pull-ups tend to work better when your form is VERY careful and precise, and the fast-paced nature of programs like P90 sometimes -- sometimes! not for everyone! -- discourages that).
But the biggest thing that will help you see progress is...tracking progress. If you didn't write down where you started before you began P90X, and where you were after 30, 60, and 90 days of it, then you might be doing a ton better than you think you are: Gradual progress is difficult to see if you're not tracking it. So whether you decide to change your routine or not (it could probably be a bit simpler and still work; however, if P90X is working for you in the sense that you're sticking with it and you like it, then keeping it might be better), start tracking what you lift, how many push-ups you do and your body measurements (not weight! You're weight-training, so you're not going to lose much weight), and see if you aren't in fact making more progress than you think.