Update - Mortgage Insurance Payments are Deductible

Unfortunately it's not retroactive, but yes, MI (or PMI) payments are income tax deductible starting January 1st 2007. Any new mortgage insurance policies written after the new year will be deductible.

According to BankRate.com there are some caveats:

Caveat No. 1: The tax deduction applies only to mortgages that are closed in 2007. If you have a loan with mortgage insurance in 2006, you won't be able to deduct the premiums in the 2007 tax year unless you refinance in 2007.

Caveat No. 2: There are income limits. You get the full deduction if your adjusted gross income is $100,000 or less. The amount you can deduct phases out rapidly after that, and no mortgage insurance deduction is available if you make more than $110,000.

Caveat No. 3: This is a one-year deal, and Congress would have to renew the deduction to make it apply for the 2008 tax year and beyond. Congress probably will extend the deduction, but you can't know for sure.

Caveat No. 4: If you take the standard deduction instead of itemizing deductions, the new law makes no difference to you. "You need to have a mortgage of about $130,000 or so to even pay enough interest to hurdle the standard deduction," says Bob Walters, chief economist for Quicken Loans. In practice, he says, this means that the deduction is available to households with incomes between $50,000 and $100,000.

For more on the specifics and how mortgage insurance compares to taking a piggy back loan, please see BankRate.com.