Cook shells according to package directions; drain.
Rinse with warm water.
Lay flat on a baking sheet.
Preheat oven to 350 degrees.
Cook ground beef in a large skillet over medium-high heat until browned.
Drain off fat,
Stir in cream cheese and chili powder and 1/4 cup cheese.
Spread 1/2 cup of salsa in each of tow ungreased 2-quart baking dishes.
Arrange the filled shells on top of the salsa and pour the remaining salsa over the tops of the shells.
Bake covered for 15 minutes.Sprinkle the cheese on top and bake, uncovered for 15 more minutes or until heated through.