When i use p90x should i cancel Pop or soda out of my nutrition program? What could i replace Soda with?

Absolutely, you will get much better results. You replace it with water! Lots and lots of water!

Yes. Soda is definitely not in any kind of nutrtition plan.

Drink water.

I used to be a HUGE soda drinker. When I dropped the soda, i went through a weird kind of withdrawal phase. I was miserable. So I bought a couple of those Crystal Light water mixes. I drank one or two of those a day (along with 4 or 5 additional glasses of water) each day for the first two weeks. Then I dropped the Crystal Light (It's better to drink only water.)

It worked for me, it may work for you.

Water, water, and even more water.

if you're thinkingm what about diet sodas? dont!