COOK spaghetti as directed on package, omitting salt.
MEANWHILE, cook and stir vegetables in hot oil in large skillet on medium heat 3 to 5 min. or until crisp-tender. Add reduced-fat cream cheese, milk, Parmesan and oregano; mix well. Cook on low heat 3 to 5 min. or until cream cheese is completely melted, stirring frequently.
DRAIN spaghetti; place in large bowl. Add sauce; mix lightly.