Melt margarine in a saucepan over medium heat. Add garlic; saut� 1 minute. Stir in flour. Gradually add milk, stirring with a wire whisk until blended; cook minutes or until thickened and bubbly, stirring constantly. Stir in cream cheese, cook 2 minutes. Add 1 Parmesan cheese, stirring constantly until it melts. Pour over hot cooked fettuccine; toss well to coat. Top with remaining quarter cup Parmesan cheese, fresh parsley, and pepper.