In a large bowl, cream the butter and sugar until light and fluffy.
Add eggs one at a time.
Beat in vanilla.
Combine Flour, baking powder and soda, whisk then add to creamed mixture alternating with the sour cream.
Fold in chocolate chips.
Pour into greased and floured 10" Fluted Tube (Bundt) pan. Bake @ 350 F for approx 60-65 minutes until a tooth pick inserted near the center comes out clean.
Cool for 10 minutes then remove to a wire rack to cool completely.
Glaze:
In a sauce pan, melt chocolate chips and butter on a low heat.
Remove from heat and whisk in confectioner's sugar, milk and vanilla until smooth.