Are closing costs tax deductible?
Buyer-paid points usually are deductible in the year they are paid for an original mortgage. A plain-English discussion from TurboTax is here:
Deducting Points from TurboTax
Below is a link to an IRS fact sheet on this subject.
Here is a link that might be useful: IRS Fact Sheet
Refi's are a little different. My accountant explained that on a refi, they are deductible but are split over the length of the loan. So if you refi'd to a 15 year loan you'd get to deduct 1/15th of them.