Starting from this year (2011 tax year), Ontario property tax credit calculation and payment have been taken away from the personal income tax return.
You still have to apply for the credit on personal income tax return. The government will calculate the credit (based on your property tax / rent payment and income) after your return is filed.
The total credit of Ontario sales tax credit (OSTC), Ontario energy property tax credit (OEPTC - formerly called property tax credit) have been combined into Ontario trillium benefit, if your income is not high, you will get monthly payment of the benefit instead of a one-time tax refund.
The credit is similar to CCTB payment, the difference is you have to apply for it every year on your return and provide rental / property tax payment numbers.
The procedure actually started from last tax year, your 2010 property taxes / rent payment served two purpose: one was the OEPTC credit on tax return included in tax refund; they were also used to calculate the 2011 OEPTC credit. If eligible, the credit was (or will be) paid in four instalments - July 2011, December 2011, March 2012, and June 2012. (after June 2012, the quarterly payment will be changed to monthly payment). If you had your OEPTC as tax refund last year, you should also have got these payments. If not, you can file a T1ADJ to change your 2010 return to apply.
If you used TaxChopper last year, you should have answered two questions, the first one is if you claim OEPTC for 2010 and the second one is if you apply for 2011 OEPTC. If you answered YES to the first but No to the second, you would get an alert.
The page has a link name "Credits for Property Tax, Rent etc".
For married person, the link only appears under the spouse whom you designate to claim the credit on behalf of the family at page Tax Situations
Usually the benefit is the same regardless which spouse claims it, because it is based on family income. However, there is one exception, if one spouse is 65 years or older and the other is under 65 in 2011, letting the senior spouse claim is better.