Since you vacated the property completely in 2008, it is considered rental property during 2009, as stated in IRS Publication 936, thus your rented property will be covered by IRS Publication 527.

According to irs.gov publication No. 527, it appears that you are utilizing the property as rental not for profit, you must fill up form 1040 or 1040NR, line 21. If you are using this form you can take into account mortgage interest and any qualified mortgage insurance premiums with the condition that the property is used as your main home or second home.

-quote-

"Presumption of profit. If your rental income is more than your rental expenses for at least 3 years out of a period of 5 consecutive years, you are presumed to be renting your property to make a profit.

Postponing decision. If you are starting your rental activity and do not have 3 years showing a profit, you can elect to have the presumption made after you have the 5 years of experience required by the test. You may choose to postpone the decision of whether the rental is for profit by filing Form 5213. You must file Form 5213 within 3 years after the due date of your return (determined without extensions) for the year in which you first carried on the activity or, if earlier, within 60 days after receiving written notice from the Internal Revenue Service proposing to disallow deductions attributable to the activity.

Second home rented out. If you have a second home and rent it out part of the year, you also must use it as a home during the year for it to be a qualified home. You must use this home more than 14 days or more than 10% of the number of days during the year that the home is rented at a fair rental, whichever is longer. If you do not use the home long enough, it is considered rental property and not a second home. For information on residential rental property, see Publication 527."

-end of quote-

When you vacated the property, did you then buy another property to live in, or was this co-op the only property you were buying? That information would help in researching this question.

If you look at the online calculator for the AMT (http://apps.irs.gov/app/amt2009/index.jsp?ck), it tells you to fill out your 1040 to line 44, then answer some questions. One of those questions is "Did you receive or claim any of the following items in this tax year?" and one item in the list is "Interest paid on a home mortgage NOT used to buy, build or substantially improve your home." Does this shift from home to rental property change the nature of the deduction? This is what you're asking here, but this looks like a very good question to ask the IRS itself. Look at the bottom of this answer for the contact information for the IRS, if the rest of the answer isn't exactly what you were looking for.

I don't know your answers to questions on that AMT Calculator to proceed past that point, but I will point you in another direction that might at least help offset the AMT: the 1040 Schedule E (http://www.irs.gov/pub/irs-pdf/f1040se.pdf) is the "Supplemental Income and Loss" is for individuals and includes rental property information. There are expenses involved with renting property, and this is where you take them into account.

From the Tax Tips from: http://www.irs.gov/taxtopics/tc414.html Rental Income and Expenses

>>>Generally, cash or the fair market value of property you receive for the use of real estate or personal property is taxable to you as rental income. You can generally _deduct expenses of renting property from your rental income_. Income and expenses related to real estate rentals are usually _reported on Form 1040, Schedule E_ (PDF). Income and expenses related to personal property rentals are reported on Form 1040 (PDF).

Most individuals operate on a cash basis, which means they count their rental income as income when it is actually or constructively received, and _deduct their expenses as they are paid_. If you are a _cash basis_ taxpayer, you cannot deduct uncollected rents as an expense because you have not included those rents in income. If a tenant pays you to cancel a lease, this money is also rental income and is reported in the year you receive it. Do not include a security deposit in your income if you plan to return it to the tenant at the end of the lease. But if you keep part or all of the security deposit during any year because the tenant damaged the property or did not live up to the terms of the lease, this money is taxable income in the year this determination is made. If the security deposit is to be used as the tenant's final month's rent, you include the money as income when you receive it, rather than when you apply it to the last month's rent. <<<

Did you deduct your expenses from the rent you collected? Did you keep track of your expenses when you collected rent? This is a point in time when you should calculate what the acceptable expenses ARE and report it on Schedule E, if appropriate.

Another answer posted here has a link to an IRS form that says you can deduct the interest if the house has been refinanced, but you asked about renting. So I would skip that other form.

I haven't had to fool with the Alternative Minimum Tax (AMT) so I will stop here in my research, and suggest that you simply call the IRS if these forms and notes don't give you enough information to finish your taxes. This time of year it is easy to get through. I prepared my taxes last week and had a question about my son and the child tax credit. I got through right away and the answer was achieved after being forwarded only once. Their customer service really has improved dramatically.

That said, like any other business you call for assistance, have a pen and paper ready and when that agent answers, they will give you their identification number, if not their name. Be sure to write it down, and keep notes, including the day and time you call. If you later have to write any letters regarding this matter, having that information is a big help.

Here is the page with the call in information: http://www.irs.gov/help/article/0,,id=96730,00.html

Live Telephone Assistance
When calling, you may ask questions to help you prepare your tax return, or ask about a notice you have received.

Telephone Assistance for Individuals:
Toll-Free, 1-800-829-1040
Hours of Operation: Monday – Friday, 7:00 a.m. – 10:00 p.m. your local time (Alaska & Hawaii follow Pacific Time).

Telephone Assistance for Businesses:
Toll-Free, 1-800-829-4933
Hours of Operation: Monday – Friday, 7:00 a.m. – 10:00 p.m. your local time (Alaska & Hawaii follow Pacific Time).

Good luck in finishing your taxes early, and easily. By way of disclaimer, I am not a tax professional, but I have been preparing my own taxes for years and try to understand the forms and fill them out myself, then ask for advice it needed. I think that is what you're doing also, and while Mahalo doesn't substitute for the advice of a paid tax preparer, hopefully these answers will point you in a helpful direction.

I hope this link will help you, http://www.irs.gov/newsroom/article/0,,id=136889,00.html .

For assistance, you can contact your local office. See http://www.irs.gov/localcontacts/index.html

You may also see:
http://realestateqa.blogs.nytimes.com/2009/01/28/the-alternative-minimum-tax-and-mortgage-interest/
http://moneycentral.msn.com/content/Taxes/Taxshelters/P33512.asp