Mmmmmmmm!!! Nummy nummy, this is the best white bread I've ever made, and a whole loaf was just devoured in one meal. This is so light and fluffy on the inside with an incredible crust. Got this from another site.
Place margarine and buttermilk in a small saucepan and heat until margarine is melted, or microwave until melted. Cool to luke warm.
Place sugar, salt, baking soda, buttermilk mixture and yeast in large mixing bowl.
Add flour a little at a time, mixing until not sticky.
Turn onto a lightly floured surface sprinkle some flour on top of the dough; knead for several minutes, the more you knead, the more it will rise!
Place in a greased bowl, and turn once. Cover with a cloth and allow to rise in a warm place until double in size, around an hour to and hour and a half.
Punch down the dough and place in a loaf pan that has been sprayed with cooking spray and floured. Spray the top with cooking spray, and allow to rise 40 minutes.
Bake in a pre-heated 375°F oven for 10 minutes, then turn around and do it for 10 more. Turn down heat to 350°F and bake for about 7-12 minutes more. The loaf is done when evenly browned and hollow sounding when thumped.