Lightly brown the sausage in a large skillet over medium heat. Remove from the pan and drain on paper towels. Set aside.
Grate the cheese on a box grater. Set aside.
Cook the pasta according to the package instuctions and drain. Set aside.
Pour the milk into a microwavable container and heat until warm - about 2 1/2 minutes.
In a large stock pot or dutch oven, melt the butter over medium heat. Whisk in the flour and cook for 1 minute, stirring constantly. Gradually add the warm milk, whisking constantly until it has all been added. Cook, stirring very frequnetly to prevent scorching, until thick - about 5 minutes. Reduce the heat to low and gradually add the shredded cheesestirring constatly until metled. Add the salt and mix well. Add the pasta and sausage to the pot and mix well. Add additional salt and pepper to taste. Serve immediately.