Chop bell peppers and onion. Cook in a large skillet coated with cooking spray over medium-high heat 5 minutes or until vegetables are tender.
Whisk together eggs, salt, and pepper. Add mixture to skillet, and cook, without stirring, until eggs begin to set on bottom. Draw a spatula across bottom of skillet to form large curds. Sprinkle with cheese, and continue cooking until eggs are thickened but still moist. (Do not stir constantly.) Remove from heat. Serve immediately with whole-grain toast.