Im 6'3 and 285lbs an i got alot of belly fat with the P90x what would your estimation of my weight be?

It depends on you dude. If you follow the nutrition plan exactly and never cheat, you'll probably lose a lot of weight. The nutrition plan is the most important thing for losing weight. Belly and love handles are lost in the kitchen, not the gym.

I estimate your weight to be around 285.

Just kidding, but like Austin said, it depends on you. I myself am 5'9" and weight about 190, but I don't consider myself overweight. I'm fairly athletic and quite dense, thus I weigh more than you would expect by looking at me.

If I had to estimate, I would say you could get down to 215. Of course you could go way below that or way above it, just depends how much muscle you're building and how well you stick to the nutrition plan.