Tax Rebate on interest paid for two flats?

I have purchased two attached/connected (registered seperately) flats at west bengal after taking loans from two different banks. none of the flat is put on rent. I am working in faridabad, other than the town my flats are setuated. can the interest paid for both the loan be deducted from my salary for tax calculation? As no income is really realised from rent from the second flat, how to calculate the income from house property? please suggest me the best possibile option to save the tax on account of income from house property.

What if the service tax paid in excess?

We have paid service tax in excess. There are no further transactions after the payment. Can we sefoff the excess balance of service tax paid to the sister concern by way of transfering some bills raised in the sister concern to the company in which ST actually paid by way of JVs?