Preheat oven to 325 degrees. In a very large bowl, cream butter (or margarine) until very light; slowly add sugar until mixture is very light and fluffy. Beat in eggs one at a time. In another bowl, sift flour, baking soda and salt together. Add flour mixture alternately with buttermilk to butter mixture. Begin and end with flour. Mix in lemon peel and juice. Pour batter into greased and floured 10-inch tube or 12-inch bundt pan. Bake for 65-75 minutes or until toothpick inserted in center comes out clean. Place pan on rack for 10 minutes to cool. Turn cake out of pan onto rack. Spread with as much lemon icing as the cake can absorb (about a third of the icing) Allow cake to cool completely then frost with remaining icing. Icing: Blend sugar and lemon juice together and drizzle over cooled lemon cake