Since you own the property already, you can find out your existing tax rate by reading your bill. If you can't find that, anyone can look up their tax bill at the county assessor's office online, or by phone.
By free and clear, I am assuming you have no mortgage on the property. That information is relevant for considering income tax advantages to owning real property, not in terms of taxes directly paid on the property. On income taxes, they have recently removed the passive loss deduction of up to $25,000 allowed each year...if you make more than $125K in income. So as of 2009, if you had expenses you could write off, like interest paid on a mortgage or taxes over and above what was received in rental income, as well as depreciation, those deductions may no longer be valid. Speak with your tax professional on your personal situation to see how that applies to you.