In small bowl, combine cream cheese, garlic powder and pepper; blend well. Spread 2 tablespoons cream cheese mixture on each tortilla. Sprinkle about 2 tablespoons each of spinach, bell pepper and cheese on half of each tortilla; fold tortillas in half.
Heat large nonstick skillet over medium heat until hot. Place 2 folded tortillas in skillet; cook 1 to 2 minutes on each side or until golden brown.
Remove quesadillas from skillet; place on platter. Cover with foil to keep warm. Repeat with remaining folded tortillas. Cut each quesadilla into 4 wedges. Serve warm.