As an aside, a ZIP code is not a point, it's an area (assuming that you mean US-American ZIP codes), so calculating a distance around that will be tricky, to say the least.
Joined: Jan 16, 2010
There is a web service through which I am fetching all the address details passing ZipCode through the DataBase.
Now I have to create enhance it to fetch the latitude and longitude details when I pass the partial address.
I cannot add a new datasource to the existing web service.