Cook pasta according to package directions; drain. Meanwhile, in a medium bowl combine spinach and crabmeat.
Cover bottom of a 2-quart square baking dish with 1 cup of the pasta sauce. Top with pasta. Top pasta evenly with crab mixture. Sprinkle with 3/4 cup of the cheese. Top with remaining sauce. Sprinkle with remaining 3/4 cup cheese.
Bake, uncovered, in a 375 degree F oven for 30 to 35 minutes or until sauce is bubbly around edges and cheese is slightly golden brown. Let stand for 10 minutes before serving. Makes 6 servings.