If you have a business in mind and want to know what it will cost you check out bplans.com Its a nice american site with details and sample plans on various industries.
The sample plans that are given on the site are quite exhaustive and exciting. It gives sample costings for various industries including break-ups of cost heads and thier graphs
But the only problem is that all the costings are done in dollars and are relevant to the american industry.
Also some industries are not relevant in the Indian context (horse reseller).
But nevertheless the site is a good reference for someone who wants to get into business or who is already business