In an oven-proof medium skillet (cast iron works great) over medium heat, brown sausage, stirring frequently to break the sausage up into small bits. Drain any excess grease. Return to the skillet, over medium-low heat, stir in cream cheese, salsa, and taco seasoning. Stir until the cream cheese has melted. At this point you can pour mixture into an oven/microwave dish; cool and refrigerate. If serving immediately, top mixture with cheese, put into a 350 oven until the cheese has melted. If you are reheating from the refrigerator, top the cooled mixture with the cheddar cheese and bake in a 350 degree oven 15 - 20 minutes or until hot and bubbly. You can also heat in the microwave - top with cheddar cheese, cover and microwave on high in 30 second increments until hot and bubbly. Serve with tortilla chips.