Coat a 10 inch nonstick ovenproof skillet with nonstick cooking spray, and add the onion, bell peppers and ham. Place the skillet over med-high heat, cover, and cook, stirring several times, for about 3 minutes or until the onions and peppers start to soften.
Add the potatoes to the skillet and stir to mix. Reduce heat to medium, cover, and cook for 1 minute or until the mixture is heated through.
Reduce heat to low and pour the egg substitute over the potato mixture. Cover, and cook without stirring for about 10 minutes or until the eggs are almost set.
Remove lid from skillet and wrap the handle in aluminum foil (to ensure it will not be damaged by broiler flame.) Place the skillet in a preheated broiler and broil for about 3 minutes or just until the eggs are completely set. Sprinkle cheese over top and broil for another minute or until the cheese is melted.
Cut the frittata into wedges and serve hot.