Preheat oven to 350 degrees.
In a mixing bowl, cream butter and sugar.
Add the eggs, one at a time, beating well after each addition.
Beat in vanilla.
Combine the flour, baking powder, and baking soda.
Add to creamed mixture alternately with sour cream.
Fold in chocolate chips.
Pour into a greased and floured 10 inch fluted tube pan.
Bake 60 - 65 minutes or until a toothpick inserted near center comes out clean.
Cool for 10 minutes before removing from pan to a wire rack to cool completely.

Glaze:
In a saucepan over low heat, melt chocolate chips and butter.
Remove from the heat; whisk in powdered sugar, milk, and vanilla until smooth.
Working quickly, drizzle over cooled cake.