When I get a craving for pizza, i usuall scrape the bulk of the sauce off.... leaving a bit. I've looked at a LOT of pizza sauce carbs and I know that commercially prepared sauces usually have sugar, and that amount of sugar usually increases if it's a resturant prepared sauce..... so... eating the sauce is where you're going to get a TON of carbs.... but I usually leave a smidgen on. Of course, my friends usually get weak and eat the crust so I KNOW I'm better off than they are anyway.
If you do crave pizza, they do have low carb pizza crust mixes out there. CarbSense (I think) makes a really really yummy one. I've only had it once but I swear I didn't feel like a single thing was missing!